Hey, I am also 15. That seems like alot of exercising. (i play soccer (intense) 3 times a week, and try to work out 3 days a week). You should run for at least 30 min every sec. Day (every day may be too much). Also, its more on the reps then it is on how many you do in a row. Try to do 50 in a row, and do at least 3 sets. (the last 10 should be hard to do).
Eating fibre helps your abs.
There are a ton of exercises out there!
Reply if you want to talk some more (i'm kind of rushed right now)
ps: you can work your abs everyday, but any other "big" muscle you should only do every second day-1 day of rest
