My family’s Christmas traditions are warm, fun and pretty low-key: We decorate a tree, hang some lights, get on with some truly off-key but hilarious renditions of carols. Usually we do so two weeks before Christmas itself but, this year, it all happened just a few days beforehand — because not all of us were home yet.

After years of holidays as a family who all lived in the same place with the same routine, my oldest is out of the nest — away at college, in his second year. As a freshman he rushed home, but now he has his own life and commitments on campus. He has fond memories of Christmas and would have been crushed if we didn’t wait for him, so we decorated the tree on Friday when he came home.

There’s a stage before empty nest but after sending your first child off to college that we don’t really talk about in terms of parenting. It’s the space in which, if your child is anything like mine, they take tiny steps toward true adult independence but then retreat back to the familiar patterns of home at the holidays. Only, in that stage, they might bring a date, might blithely tell you they won’t be sleeping at home that night (or that week) because they’re staying with their new partner.

My son is a good big brother, a wonderful son and, these days, he’s living about two hours away from what has long been our home together. He’s earned a great academic scholarship, has a part time job, good grades…. and what appears to be a serious relationship. No kids means no Christmases away from home yet. But I can see those holidays coming; I saw the first glimpse of them at Thanksgiving where, instead of being underfoot in the kitchen, he was in the corner making his partner comfortable in the midst of the dull roar that is 10 people in a two-bedroom apartment.

Now, there’s nothing wrong with his partner, no reason for me to balk; he is an adult child, over 18, living mostly independently, and I know that the day is approaching where my house will stop being his home because he’ll have their own. But even knowing it is coming, it still stings.

He doesn’t remember the Christmas-that-wasn’t, a few months after I divorced my ex-husband, who immediately stopped paying any form of child support or insurance. I couldn’t afford a Christmas tree that year until after Christmas, but he was a toddler and I reasoned (while I cried in the bathtub) that he was too young to know what day it was, anyway. Yet, I knew, and I cried.

I made sure that every Christmas thereafter was special and planned for well in advance. His dad — the man I married 4 years later — comes from a family that goes all-out at Christmas so, even when we were just dating, he was all in on the season. A year in, he wanted to stay with us for Christmas and watch the child that called him Patchers (Patrick was still too hard to say) open the gifts he’d given him.

We were in college, but I was his much-older (by 4 years) girlfriend-with-a-baby going to school after military service and a messy divorce. It didn’t necessarily seem like we were going to be a forever-family yet — not then, when my baby was only 3 and anything could happen with a boyfriend.

(That Christmas, though, was the first of many as a family; we’re up to 17 together now. And even though my son can say “Patrick” now, he calls Patrick “Dad,” and they have their own amazing relationship.)

That first holiday together, though, wasn’t perfect, because he and his mom had a fight before it about what was his first Christmas away from the family.

And now I know what I didn’t understand when I was the partner that my mother-in-law had some side eye for, because I am starting to feel it myself. She wasn’t happy with him that first Christmas he wasn’t with her, but she welcomed me into the family anyway, embraced me as her daughter and my oldest as her grandchild and adjusted her Christmas expectations to include our traditions.

But, like my mother-in-law — other than a little grumbling — I will keep whatever I feel about our eventual first Christmas apart to myself. Because the family that my son and his partner are forming is special too, and they learned how to be in a family from being in my family.

This year, his partner isn’t going to be at our house for Christmas — there’s a trip back home to Beijing on the itinerary — but my son will be here. We are going to argue about something silly like who has the best songs, and there’ll be an amazing amount of food consumed. We’ll decorate and sing and be silly, and I’ll savor these last fleeting moments of the time before he moves on to creating his own traditions.

It isn’t like we’ll never spend the holidays together, it isn’t like we won’t talk all the time, and I know he’ll always be my first baby. But I’m no longer raising my child; I am getting to know my baby as an adult, and it’s more bittersweet than I expected. Still, the happiest holidays are sometimes the most complex, and they’re beautiful.