i started when i was 12 and all of the other kids were like, 5, 6, or 7. it was a little awkward at first. but with me was a woman who was 28 and one who was around 50. so, don't worry! it's absolutely fine. if you feel uncomfortable, you can go for private lessons or with a friend your age, but i have to say,group lessons are more fun! ^^
go ahead and go for it!
you are gonna have tons of fun and it's an experience you'll never regret!