I am 13 and 215 lbs. Need some advice!?

Well, i'm 13 and 215 lbs. I need to know how to lose weight and keep it off. I am eating healthy so don't bring that up. I need exercise advice. Someone told me that i should not go to the gym just do it all at home. Should i go to the gym for 1 hr a day? or do it all from home? What exercise times and plan could i use to get to 175 lbs in a year? Thx for reading and the most informative answer gets best answer and 5 stars!