My husband tells me that when the tractor was invented, farmers who spent their lives learning to be great with horses had to rely on young farmers who understood machinery. It was an era when young people looked like experts in farming almost overnight.

Or at least they felt that way. Really, though, they were experts in the machinery of farming, but machinery so quickly became a focal point of farming that being an expert in machinery meant you could get by. For a while. Until a drought. Or a flood. Or until you need to earn a lot more money to support your family.

This is the best example I can think of to explain the situation that Gen Y is in as they enter the workforce already being experts in the digital realm.

Today online advertising is growing at the rate of 33% per year. The fastest growing careers are software development and marketing specialists. And as more of the U.S. market share for advertising tips to mobile advertising, more of the workforce needs expertise in living their lives on their phone. And you know no one knows about that more than Gen Y.

So how do companies hire to fill jobs for cutting-edge technology intersecting with mobile advertising? College kids have deep knowledge in both fields, so companies hire kids right out of college to do these jobs.

We hear a lot about the 20-year-old developer making $100k in Silicon Valley. But what about the 23-year-olds in marketing? What happens to them?

1. They rise very fast.

The first thing that happens is they get invited to very high-level meetings, because senior management expects the company to lead the way in online marketing, and older professionals often lack knowledge of the newest trends. Experienced professionals can manage, yes, but when it comes to using Plague, it’s hard to find someone in middle-management who knows what they’re talking about.

So the just-out-college kid is conferred immediate authority in their career by being thrown into meetings with senior level managers. Do you want to know how intoxicating it is to talk with a knowledgable teen about social media trends? This post by a teen about teen usage was so popular that he wrote a second.

2. They get a slew of amazing brands on their resume very fast.

Jim Durbin is a recruiter for digital talent for advertising agencies. He says the biggest problem in his field is that the young people get recruited very early, and then get thrown into meetings with one big brand name after another. The kids have no knowledge of how businesses run, or how meetings progress, but they continue to be tapped for their particular expertise.

Client-side, the digital talent job hops. As soon as you have some experience, you can get a job that requires five years experience. And after you have a job with manager in the title, you can get a job that looks like middle management. You don’t know how to manage, but it’s okay. Your job is just to be the person who assures the CEO that middle management has a grip on the latest online marketing trends.

3. They work from home.

1-800-Flowers has been recruiting for a director of digital marketing for a long time. I love the company. And I want flowers every day. I asked what the pay is. My contact said, “It’s great pay. But it’s in Florida.”

End of conversation.

Digital marketing is in high enough demand that if you’ve got that up and down your resume, you can work in any location you want. Which is probably from home. Or Thailand. Or anywhere that is not the company’s headquarters.

Cassie’s career has had this trajectory and she tells me how bad it is to negotiate special dispensation from company policy so you can work from home. “It sucks,” she says. “Because everyone knows you’re the person working from home and they hate you for it. Every conversation on the phone begins with, ‘So how is it working from home?”

4. They try consulting.

So Cassie did what all people do when they are in high demand and they want to work from home: she became a consultant. At first, she made a lot of money, selling to all the clients she had when she was on a permanent staff. She knew what they needed and how to get it to them, and consulting was Easy Street.

But after a while, consulting gets harder. Because if you rise up in your career this fast, you are very specialized. And that specialty is hot for a while, but nothing stays hot too long.

I rose very fast in my career by being one of the only people who had experience getting a Fortune 500 company onto the Internet. But marketing myself as that person only worked until everyone else was on the Internet too.

Cassie rose fast by having close ties with an enormous list of bloggers who would work with her. But marketing herself as that person didn’t work as well when it became clear that banner ads on blogs wasn’t working anymore. Or ever.

Consulting is a difficult business and it’s where the playing field starts to level off. Other people, who don’t go the route of consulting will also find that the playing field levels off when they high enough up the ladder that being an expert in a fleeting-but-cutting-edge field is no longer an effective calling card: it’s left them too narrow.

5. They need a big idea.

That’s when you need a book. I know I’ve been saying for years that no one needs to write a book. Because books don’t make money. I mean, they do, but only in the way lottery tickets make money.

What I have noticed, though, is that a book forces you to have a big idea. And the second half of a career require big ideas.

Most careers top-out around age 35. You know how Hollywood stars have a hard time transitioning from child-actor to adult? Or from action-hero to old guy? Those career transitions are difficult in the non-Hollywood world as well. There’s a book about companies called What Got You Here Won’t Get You There. And that’s not just true for companies, it’s true for individuals as well.

The thing that gets you past the career plateau of a high-performer is a big idea. This is not something you have to get on the cover of Fast Company or the top of a bestsellers list. It’s something you need to just write, page by page, because when you are clear enough to get ideas into book format, you are clear enough to use that idea as a guiding star for the next half of your career.

Somewhere between the age of 30 and 35 you need to have a big vision for where your arena is headed and how you are going to be a part of that. A blog post is a small idea. A book is ten of those small ideas that add up to something big. (It’s hard to come up with that idea. Even professional writers often get a rejection from a publisher that says, “I think it’s an article, not a book.”)

This book, assuming you have one in you, is something you might give to potential consulting clients, you might share with work friends as a way to let people know what you’re thinking, but the first audience for your book is you.

6. They recalibrate.

Remember the kids on the farms who learned machinery instead of horses? They could farm so much faster than the older generation that those young mechanics felt untouchable.

But my husband explained to me that in the end, everyone still had the same hay bales, stored in the same red barns, and what you did with that hay determined the life of the farm.

I imagine the piles of hay that came in early for the people who harvested without horses. I imagine them sitting at the edge of their full-to-the-top barn thinking, “Now what?”

It’s intoxicating to rise fast. When I think about my past lives, I don’t think of the thrill of walking around the pro-beach volleyball tour in a bikini, my perfect body, signing autographs. I think about running around my high-rise office in gorgeous DKNY clothes and Via Spiga shoes bestowing ideas upon underlings thrilled to work at my startup.

I told myself I’d never give that up for parenting. Even when I was a parent I said I wouldn’t give it up for parenting. But I did.

I didn’t give it all up. But I gave some of it up.

There’s a reason that CEOs of Fortune 500 companies earn more money per year than the entire population of some small countries: The CEOs give up their lives for their work.

You are not likely to want to do that. At some point in the career of a fast-rising star, there’s a recalibration. A foot on the brake.

And it’s nothing to fear. It’s just another change. Like any other step in the trajectory of life for a fast-rising star.