Those footballers are not highschoolers by any stretch of the imagination!

It's a movie and they are actors. Can't always find decent actors for a movie that just happen to be the exact age of the characters. You how many actors have played high school kids when they were actually a lot older? A lot. Rachel McAdams was 26 when she played a 17 year old in mean girls, nobody cared. The guys in this movie can pass as high school guys.