I'm actually starting to worry about my future concerning my body

[King16]

Before I have always found a way to get to the gym comfortably on accident, but this is my last yr of school. I'm wondering what am I going to do about gaining muscle. I have been doing bodyweight exercises for the last 2 weeks at randomn mostly, just to at least hold on to some of my muscle. Wht I'm wondering is if I can turn this whole bodyweight exercise thing into more of a permanent muscle building regimen until I get out of highschool(going to a college with a gym, and gettin a car when i graduate, so i can go to other gyms if needed). If anyone has any links or personal advice on what i could do for my legs to get more size and mostly my chest, because when working my chest in the past doing bodyweight stuff like pushups mostly, I only managed to get the middle of my chest more indented over time, but no mass that was noticable. Any help would be apprecaited. I am mainly worried about gaining muscle but advice or links to articles or something about strength gain would also be greatly appreciated. Also what would I have to change about my diet for this to work as far as muscle and size go?