First cavity @ 29 yrs old

I went to the dentist last week, and got some bad news! I HAVE 2 CAVITIES!!!!! I have never had a cavity in my life, and now, 1 week before my 29th birthday I have 2, how does that happen? I thought you grew out of things like that, but I am told it is the opposite. No one goes through life without a cavity (or so they told me at the dentist). So today I had my first cavity filled, and I was TERRIFIED! It wasn't as bad as I expected, but it didn't feel good. The left side of my face is numb, and I tried to put some chapstick on before I left.....bad idea, it was all over my face. Back to the dentist Monday for filling #2. YUCK!