Cubing does not ask how old you are. (Unless someone is 6 months old and prone to try cubing with teeth which includes a danger of swallowing sticker pieces or even whole corner/edge (whichever dislodges first).
I'm 3x older than you. It might be considered weird to compete with schoolboys, but I don't think about the age difference. Most of the people I meet on competitions are better than me, there are always some new kids who are worse than me. That does not matter.
Last competition I went around and tested each and every type of 4x4 cubes available (except the QJ-s, what I had already). Everybody is willing to let you try their cube(s) unless they are in a hurry for the competition round. Most will tell you the whole story behind the cube (when, where, how much, stickers, lube, springs etc.)
Just be polite and you get the same in return.
It's good to see other people solving the cube and others will watch you also. Don't get nervous about that. When you sit down on the competition desk, you must do your thing and everybody is able to stare at your solves. It's normal.
Compare it to car enthusiasts gathering - it's almost the same questions: how fast you are, what's inside, can I try, how do you do this, how's the weather. Everybody is welcome if they have some interest on the subject - cube, car, astronomy or underwater checkers.
Really, nothing to worry about.
Peedu