How did I get old?

My birthday is coming. Didn't I just have a birthday? I'm fine with getting older, I am. But it just seems like I 'm getting older faster.
Maybe I'm feeling my age. I'm starting to get fat in places that I never worried about before. And my cousins and friends who are just a bit older than me have teenagers. How did that happen?

Do you remember this scene from When Harry Met Sally? It’s how I’m feeling lately.
Sally: (hysterically crying) …and I’m gonna be 40!
Harry: When?
Sally: Someday.
Harry: In eight years.
Sally: But it’s there.