In my case, I knew early on (age 12-13, I suppose) that I was different. But I spent years in denial and living a purely vanilla life. With time, however, I was able to articulate my feelings and desires. And it wasn't until I met my current partner 3 years ago that I was in a relationship where I could more or less fully express my sexuality.

So I'm thinking the reason there are quite a few 30+ year olds might be like me.....They just needed time and the right environment to explore and "come to grips" with this part of their lives.