You've given us no clue on how old you are, so I'm going to guess you're a teenager. If you're a teenager, your hormones are all over the place - you are being to be aware of your sexuality and you probably feel the sky's the limit.
If you like this person, spend a little time to get to know him/her. Find out what his/her interests are, favorite color, do they like to walk in the rain, etc. As you find out more about him/her, you will be getting a sense of what kind of person they are. It's ok to crush on someone that's the same sex as you, to like and admire them.
Test the waters by asking what he/she feels about same sex friendships / relationships. Their answer will tell you how to proceed. If there is no interest there, then don't force the issue. This is something that you cannot control - who likes you and who doesn't. Revealing your feelings when they have no interest in you would probably be devastating for you.
Contrary to what most people think - you don't have to reveal yourself and your feelings to everyone you meet. Sometimes you just have to practice discretion. He/she may not be the one and that's ok, even though it won't feel like it. You have a wonderful life to live and will meet many people during your time on Earth. Relax and enjoy the ride. Good luck.