Need help with this girl please?

right so basically there's a girl I met back in September. At first I didn't really talk to herbut through a common subject we got talking and helping each other and over a few weeks I developed feelings for her. Halfway through march I started a conversation with her and we kept it going until a like a week ago. We texted literally everyday. About mid may time I gained enough courage to ask her out, a couple of weeks into our conversation, but we had exams that month so she said shed rather stay friends for now. The exams came and went but by this time she said she thought she liked me as more than a friend but decided over time that she didn't, but that we would stay close friends. I've met up with her outside of school 4 or 5 times, we went to London last week and her friend had a party end of may time where we nearly kissed (she pulled away). I still have really strong feelings towards her and she knows that I like her, but last weekend she went to a party and got off with another guy, seeing the pictures made me want to cry, but I swallowed it up and haven't told her about it. Now we don't text at all and she's been spending more time with the guy she kissed, and I can't help but to feel jealous. She's told me how far she's go e with a guy before, and she says itwas just a kiss but her friend doesn't want to reveal much suggesting they've do e more but she says she didn't and I believe her. I've tried ignoring her and blank g her but it's really hard not to talk to her because I like her so much. What do I do? Do I forget and move on? Do I keep trying? I fell really lost and confused. Shes 16 and im 17 but we're in the same school year. Thanks