girl crush

Recently I've developed feelings for one of my friends. I can't help but daydream about being with her. I like her a lot but the problem is she has a girlfriend that she's been dating for a year and moved to college with and now they live together. When we are with each other I can't help but feel a spark between us.  I'm not sure what to do. I don't know if it's worth mentioning my feelings to her or just hide them away. I don't wanna ruin our relationship.