What should you do if you like a girl who is a year older than you but you don't know each other?
One years different is no big deal. I'm almost 4 years older than my husband. You don't even have to bring up age. Just go up and ask this girl out. Don't live on "what ifs" or "I should have done that." Make the effort and at least you will know if she's interested in you one way or the other. Just think, if you don't ask her out you could be missing out on a good thing.