How do you deal with your kids getting older?

I’m a stepmom to a 9yo boy. I’ve known him most of his life (since he was 3 months) but only parented/lived with him since he was 4. It really feels like time has just flown by and I’m going to blink and he’ll be in high school. I have this strong sense of grief about how I can’t go back. Of course I’m so excited to continue watching him become and grow…but man is it a gut punch some days to remember how little he used to be and how quickly hes growing up. And then I realize someday I’ll feel that way about the age he is now.

It’s complicated a bit by feeling like the first few years I lived with him I was finding my place/role in his life so I feel like I wasn’t as present as I wish I would have been.

Anyone else? Is this just the bittersweet wonderful awfulness of being a parent?