You have the hard part out of the way (figuring out whether your crush is mutual). The next step is to approach her and start talking. Use lots of eye contact and smiling. You could start with a flirty comment such as, “A little birdy told me you have a crush on me. Is that true?” Wait for her response, but understand that she may be embarrassed. Tell her outright that you have a little crush on her as well, so she knows the admiration is mutual. It’s okay to admit that you’ve wanted to talk to her but were a little nervous.
Talk to her like a friend. Ask questions about her life and what she is interested in. Share what’s important in your life as well as your feelings. Don’t worry about impressing her. Just be authentically you because she likes you already and wants to know more! Chat frequently, send her texts, give her sincere compliments, sincerely listen to her, and sit near her when you can. Take it slowly, but those are your next steps.