you can still get in trouble for fighting whether you hit first or not, unless its defense as in they pull a weapon on you and threaten your life you can still get in trouble for it.
you dont need to be 13 to drive a dirt bike, fourwheeler, racing mower or anything like that.
fix your bike or bring it to someone like i do, i personally taught myself how to build a bmx bike from scrap that my dad found for free one day
get a job, do work around thats easy, ask neighbors for work. dont do the mistake i did and wait till you're 16 and then start working like i am now. i cant afford all my hobbies and have a few things broke that i cant afford right now that im stressing over on top of saving up for a car or truck.