Is it normal to have these thoughts about every guy i see???

I recently have found out what jacking off is, and that like EVERY guy my age does it. I think it's really weird. But, I saw some sex-ed videos and now, everytime I see a guy (EXPECIALLY my crush, since I saw a question he asked over on yahoo answers about it :O) a picture of them jerking off enters my mind. I don't know why!!! But it's like I can't control it. Now that I know the truth about what they REALLY think about about in the middle of the night, it's been on my mind almost all the time