conflicted about my feelings for her.

So i love this girl, i truly do, she’s all i think about and she’s everything I want. and she loves me back, we’ve been talking for a while now and even hung out more than i can cant, bottom line is, we’re in pretty deep, we’ve said i love you and i think it’s about time i ask her to be my gf. but i feel as if im driving myself insane thinking about this. me and her started texting a 2 years ago, we were just friends the entire time, but we both knew there was something there, she’s kind of friendly regarding that she makes friends with guys really easily, and she has never been shy initiating conversations with guys even as friends. all we ever did at the time was text and ft. naturally we were never together and never even said out loud that we liked each other so we would both talk to other ppl, essentially we were friends, but liked each other. now here’s the thing, before we knew each other, she had slid in my cousin/best friends dm’s a while before we ever even knew each other, she thought he was fine but he sort of rejected her and they never progressed. they never even talked. now fast forward to last summer, her and my cousin became friends at a fair and they became close rly quick, they facetimed a lot, sometimes she would get off call with me and then call him… texted a lot, and even went to the movies with my other cousin one weekend as a group of three,(she used to joke about liking my other cousin to “ragebait me”) the also all hung out again a couple days later as a larger group, and when one of my friends asked how iwould feel about this, she told him she didn’t care. by this time i knew i liked her. it kind of broke my heart because she never wanted to hang out like that with me, even as friends, so yes it hurt. and i realized that she never would have told me if i never found out. but i can’t blame her, she was single. i then told her everything and how i felt about it and distanced myself, we barely lasted a week before she told me she liked me back and then we started talking pretty seriously, throughout us talking we talked about the situation countless of times and she told me that if she were in my position she would have never spoken to me again. and that just felt like a slap in the face, because to me it just sounds like she never liked me as much as i liked her. she also lied about the other guys she’s kissed or been with and they are both people i knew and are guys with the worse possible reputation when it comes to girls😭 but she eventually came clean to me. everything she’s ever told me contradicted the way she treated me, she tells me she loves me but in the back of my head you would have never even treated someone you liked like that. and to be honest, i’ve always had this issue about being a second choice, especially to my own friends, it disgusts me to be honest. i hate the fact that if my cousin reciprocated her energy me and her would have never been talking now. and i hate the fact that she surrounded herself with guys she thought was fine all while claiming she liked me all along. i’m so conflicted about my feelings because i can never let this go. i truly cannot. the fact that her and my cousins are still friends and even have each others numbers, whenever i even see them as a follower or the fact that she has them added on snap it disgusts me. i don’t know what to do, i love this girl so much, but im afraid i love her more than she loves me. and i hate the way she treated me before. i haven’t told her the entirety of how i feel because im scared that if i do, things will never be the same. thanks for reading this much and i would love some advice about my current situation!