Did I tear my ACL at practice last night?

Alright, so I'm fourteen years old, five-seven, and about 125. Last night, at the beginning of football practice I was running through some defensive back drills. The drill was to backpedal for three steps and then tackle the runner at a 90 degree angle. We were rotating through and I was the running back so the pitched the ball to me and a ran upfield. The cornerback hit me rly low and his helmet struck me really hard on my mid-thigh. It was very painful for like a minute but then it became bearable so I just played through it. I noticed it last night, but now its the morning. Every time I take a step or point my toes upward, its very painful. I don't want to go to the doctor's today because I have a Spanish test. Should I just wait it out and go to school or is there a possibility I tore my Acl?