How to stop being jealous of my best friend?

So we been friends for a pretty long time were pretty close. I'm very quiet, I'm not very social at all. I mean I'm working on it. But sometimes it worse cause i have social anxiety. I don't like being this way. If i did i accept the way i am. But it always seems that when i hang out with her and our group of friends she is always the one who gets all the attention. Friends always complementing her, always more attention on her. She admitted to me she likes attention. At first it didn't affect me. It wasn't until perhaps college that it just started to annoyed me. Cause my friend always kept talking about her how pretty she is and everything over and over and I always feel the shadow, third wheel. Now if my friends are going to hang out i get invited but they make sure she going and i just get push to the side, not like it matter if i come. I don't know i don't like being jealous but it's inevitable because I am insecure and I'm not confident at all. I have talked to her about it and she has apologize, it's not her fault at all though. She notice too, if i go hang out she tells me she sorry that i didn't have fun. I have a hard time stopping myself comparing myself to her. I really really know i have to focus on myself, trying to fix things to becoming happier with myself. But it's so hard. When I'm the second choice when she is always perhaps going to be the first choice to everyone.I always over analyze everything and overthink. But she has such low confidence, she calls herself ugly, once i got annoyed with her and said "I'm tired of you saying that" and she told me "well I'm sorry that I'm saying that i really feel" when in reality ppl ALWAYS telling her she's pretty it's annoying. I feel like she seeking attention from that too. I told her and she just got irritated. In a way were sorta similar, but in many ways very different. I don't hate her though. But we always tell each other how were feeling and so I do want this friendship to work. I really need advice. Were 18 btw. How do i become more social and confident?