Maybe it's the old guy you climb with!
Or your long hair...you should try cutting it!
BO is a serious problem when trying to win friends & influence people. Also if your climbing shoes smell...try some talcum powder.
Seriously though I suspect some people just wonder how safe a 15 year old is to climb with because they assume that you are inexperienced & that young guys can be a bit gung ho! As soon as people learn that you are safety conscious (particuarly in trad & that means wearing a helmet...any helmet) & capable they will treat you as an equal. Maybe some of them are threatened if you can climb 25's @15...it doesn't take much imagination to think you can only improve in the next ten years...unless of course you become too lazy because of long walk ins & become a couch potato!
Keep going, there are plenty of friendly climbers out there...someone has given you an early advantage in the game so enjoy it!