I play football and run track and do xc in the summer and did it before i got in to highschool.
I think football would be better cause it will get u in shape maybe not as good as xc but it will get u in shape.It also gets u mentally tough and physically tough. Plus great way to start losing those summer months of fat cause u lose more weight wearing 20-30 pounds of gear in 100 degree weather.This is just my opinion there both great but if it was me i would pick Football.