Please help me I'm having a problem and I would be grateful if someone answered me! it's not a school question it is a love problem. I'll mark you as brainliest!

I have liked someone since the 4th grade. I had moved schools but the only person I could think about was that girl. I eventually saw her again and realized that I loved her. I don't know if it's weird, but I felt jealous that she was in a relationship, but was still happy because I was friends with her. I wanted to tell her my feelings for her so badly, but she was in a relationship, even now I want to tell her that I love her. what do I do?