Well, you are 16 and a senior? good for you, you must be a smarty pants, I bet your parents are proud of you.
It's normal for you to be thinking of girls all the time! you are a horny teenager and that's what happens! Even though I am not a guy, I am going to suggest that you relieve yourself in the morning before school (easy time to do so, since you'll have morning wood) then perhaps you will be able to stay on task at school. Then there is after school, do it again then do your homework and go hang out with your friends, because you know darn well that if you are going to be hanging out with girls after school, you are going to be all revved up and horndoggin' it again so go for it again.
And no, you will not go blind, grow hair on your palms or kill a kitten!
Have fun! Just watch out for ceiling cat!