My parents won't let me climb trees. I'm too old for airsoft/paintball (really, those things are for little kids). A model airplane will only end up decapitating someone, and a potato gun will end up blowing me up. Riding a bike? Isn't that for elementary school kids?
I don't know what I'm in the right age group for anymore 
-Penguin
There are no age groups for the activities you mentioned. The most important thing you need to remember (especially at school) is that the so called manners every kids of your age have concerning the ways you walk, speak, dress, study, or have fun will all change the very moment you finish high school.
There is not pre set limit or restrictions for what kind of things you can or cannot do when it comes to moving your butt out of the house. There is nothing more natural than riding a bike or playing paintball with a bunch of friends. There are phases of learning when you join an RC club and start flying a trainer plane with a trainer for the first time. The goal is to let your parents know that you know what you are doing and slowly letting them trust in your judgment and wisdom. By then, it will be time to leave the house and get an apartment and be a man.
That's just life and it's very simple. The system is what is making it look complex.