When did I grow up?

I'm not sure exactly when this happened. One day, I was living in my little apartment with my cat, without a worry or stress (other than boy troubles and what cute outfit will I wear out Friday night) and the next thing I know I have a husband, kid, step-kid and I'm talking down payments on houses, mortgage rates and which neighborhood has the better elementary school. I realize in my head that this was a gradual process, but it still seems sudden. I used to be able to go out until 2 in the morning and wake up for work the next day - now I feel like crap if I'm up much past 10. When did I get old? When did I grow up? I still don't even think of myself as a grown up. I still feel like I'm in my 20's. That's gotta count for something!!