LOL! harsh, When your younger your much more able to keep your stamina, keep fit, and don't give up, then when your old enough to go to a gym, go! Dont box without any tuition or you may pic up bad habits that are very difficult to get out of!

Be careful of using any weights because you'll still be growing and could permanently damage your skeletal structure.

Just out of interest, where do you live? uk? us?

Check out the other posts on the forum about heavy bag work, shadowboxing, and make sure you wrap your hands properly!

Good luck!