I could have written that myself mate, so i know what its like. First off, nobody will call you a peado if you go out with someone whos 15, 16, 17 etc. Without sugar coating it, you're pretty much going to have to wait it out. Theres loads you can do to make yourself appear older to other people and feel better within yourself. Get a short ish haircut, something smart and snappy, long styles make your face appear smaller and more babylike. Next, chose clothes in a more mature, fitted style, less what a teenager would wear, more adult. For example, classic looks, shirt,knitted jumper, decent shoes, blazer, straight leg jeans. Keep it fitted. You need to have a very confident and outgoing personality, it adds years to you. If you approach situations expecting people to assume youre a kid people will sense it and treat you so. Look after your body, youre old enough to get in the gym or get some weights and bulk up, it will make you look older for sure. Always carry ID, if you get asked which you will, just show it confidently and be ok about it, everywhere asks for id for insurence reasons anyway.