When you start a company, whether you’re a founder or a first employee, like I was at Birchbox, the last thing you think about is leaving. The last. You think about a million other things — the list of questions in front of you, your personal financial security, the subject line on your launch email, the FAQs on your website, the exact shade of pink on your boxes, the trash bins in the office and whether they’ve been emptied (because there’s no one else to do that) — but you don’t think about the day you’ll leave this company. How could you? If you walked into the door already thinking about timelines, stepping stones, lateral or vertical movement, why would you even bother? It’s too much work. Get a job elsewhere.

If you want to create a brand, and in the case of Birchbox, completely upend the way people shop for beauty, you have to be all in. No use in being half pregnant, as Gary Vaynerchuk would say. So you focus on building. The product, the community, the customer relationship, and if you’re lucky, the team. You build and you build, you solve and you solve, until one day you look around and you’re somewhere completely new. That thing you were building has evolved and changed, and with it your relationship to it has changed.

And at that point, you might not be right for each other anymore. At least that was the situation for me.

Katia and Hayley had the idea for Birchbox in late 2009 and launched a beta in the spring of 2010. I thought the idea was brilliant, their duo even more brilliant, and offered free labor until they were ready to bring me on board, which was July. We started sprinting that summer and didn’t stop. As with most startups, you begin by doing a bit of everything. I wrote all our marketing copy and product pages, manned our social channels, produced our ill-named “Haute Box” magazine, starred in videos, tested products, and, of course, ordered the office snacks. As the company grew, I built teams that did many of those things — marketing copy, content, social media — and partnered with them and other teams to ensure that our brand and voice remained 100% Birchbox.

And then, after six years, something started to feel different. It wasn’t that it got hard — it was always hard, and that’s what I loved. Over six years, I’d created a brand and a voice I could be proud of, one that women like me — non-beauty people — could identify with. Every day I worked to strengthen that brand. But in a mature business, I couldn’t generate the outsize impact that was possible in the early days. I felt stuck between my desire to create and the need to steadily execute what was already working. I ignored the feeling for many months, chalking it up to the tension between my role as a founder and my role as a member of the marketing team. I thought maybe I was just burned out.

The truth is, Birchbox has changed and so have I. The company I helped build is dynamic and exciting (yes, even with the current business climate, yes even with necessary layoffs)—I’m just ready for something different. I love this company more today than I did when it was young and unformed. It’s infinitely richer and more interesting now, with a vast and passionate community that grows every day. Birchbox is transforming the way women shop for beauty. But I’ve made my mark, and it’s time to step away from the day to day. As a founder, it’s your job to hire amazing people, share your vision, and teach them what you know — then let them hurl it forward.

So that’s it. The thing I never thought about, never considered: leaving. It’s hard, harder than I ever would have thought, but it’s also the right thing. I am so proud to have built Birchbox, and to have had the privilege to work alongside Hayley, Katia, and the rest of our incredible team past and present. I will continue to be a formal advisor, a cheerleader, and, of course, a customer.

And now? I’m excited to take everything I have learned from this incredible ride and apply it to something new. That’s the craziest thing: What comes next?