RE: Does age have to do with what airplanes you fly?
Having worked with teens vocationally for a few years and having trained a couple in RC, I understand where the older guys are coming from. A typical 15 year old thinks he has experience if he's done something one time. If he's done it for 6 months, he thinks he's an expert. Us older guys know better and have seen a few 15 year olds screw up royally when reality got in touch with perception. It also doesn't help when the 15 year old gets an attitude when the older guys try to tell him something. It is normal for a 15 year old to want to go straight into the coolest, fastest, and biggest stuff and then get mad when someone tells him he shouldn't.
The truth is, contrary to what typical 15 year olds think, most adults don't want to just keep you from enjoying life. What we do want is to keep you from being disappointed and discouraged, from splitting your head open, from becoming a dad (at least at 15) and any number of other bad experiences that 15 year olds commonly have because they percieved their level of knowledge and talent to be far greater than it was. You, being 15, think we just think too slow or are too old fashioned or that we underestimate you, failing to realize how truly superior to every other 15 year old in the world that you are. The guys at the field are probably trying to help you because they want to see you enjoy the hobby and stay with it. Treat them as friends, listen to them, and learn from them.
Now that the philosophy and parenting are out of the way, this is a hobby. Enjoy it the way you want to. Understand that you, being a novice with these advanced models, will probably have a major crash at least once. If you and whoever is funding you are ok with that, then go ahead. If not, then maybe an intermediate aircraft is in order to give you some more experience. Build your skill and learn from anyone who will take the time to speak to you, and have a good time.