I messed up & idk what to do next

Hey everyone, it’s my first post here but I’m so confused what to do. I met the most amazing girl online 2 years ago before lockdowns began, she’s now 20 & I am 22! She lives in a different country and we haven’t got to meet yet, but have said that we will wait for eachother. She’s such a sweet girl, I’m an awkward guy and she is the only one who has ever understood me in life just as I am the only one who has ever understood her too, we have lived similar lives, similar pasts, dreams, goals, outlooks on life and everything, we are aligned in all areas of life, have a really deep connection & I really am deeply in love with her.
Well last weekend I got drunk and made a huge mistake, It was my 3rd time drinking alcohol in 2 years, I was never really a fan of it. Well my neighbour had a party and invited a few of his neighbours over, I decided not to go but then this girl, a different neighbour came in to ask me to come cos it was fun & she said my mom who was already there wanted me to come, so I decided to go. We all drank some alcohol and had a good night, but after it this same girl neighbour came to my house again to talk with my mom & me. You see my dad recently had passed away a few weeks ago, and her mom died the week after. Well we all talked for a while and then my mom went to bed, the girl asked me to stay up with her and I did, we talked more about our pain of losing a parent and other pains in the past that we found out we shared too, we hugged and were both drunk, but also feeling vulnerable and comforted by eachother.. at this point everything was all still friendly love & comfort in my mind. She ended up laying down and asked me to hold her and I did which I shouldn’t have, then she placed my hand on her vagina which was new to me and felt good, I rubbed it for about 10 seconds before I realised wtf I was doing and stopped, she tried to kiss me but I says no, then she tried to get my number to stay in contact as friends but I said I wasn’t comfortable to do that after what happened & then I left the room. I feel like I was quite niave the whole night thinking all of this was friendly up until that final moment where she took my hand, I’ve literally only kissed one girl in my life before this and have had 0 sexual activity in my life until this moment last weekend, I didn’t even kiss this girl!

I feel so guilty and want to tell this other girl who we have never said we are boyfriend & girlfriend, but we have said we would wait for eachother, we have always been really open, honest & vulnerable with eachother, I want to tell her because I feel she should know the truth & decide for herself whether to be with me.. but if it’s more I feel guilty and really bad with myself which makes me want to tell her too. But she is an overthinker with a lot of anxiety, quite up & down at times and I feel it could destroy all trust in me when I know I will never do anything Ike this again. I would happily and easily stop drinking alcohol because I never did it often anyway and I don’t felt it would have got this far if I was sober.., also now I know not let myself be vulnerable or niave like that because I realise now this other girl was feeling attracted to me since way before in the night, trying to hold my hand at the party and other things, while I was thinking it was neighbours going through a hard time comforting eachother because I’ve always been quite an emotional/sensitive guy who is there to support others. I don’t feel any attraction to her, she’s 10 years older than me with 3 kids and I’m 22. So I will know to avoid situations like this in the future.

Sooo does anybody have any advice for what I should do? Should I tell her and risk ruining the trust because of what I did, however I feel she would believe me & forgive me.. but her mind wouldn’t let her stop thinking about it which could ruin the relationship or do keep it to myself knowing I will never do this or even put myself in a situation like this again? Thank you all for the help💜💜💜

TLDR Neighbour invited me to a party & me and another neighbour connected over some recent trauma, comforted eachother as neighbours but led to something more. Now idk if I should tell the girl I’m waiting for as I feel she should know the truth and decide for herself, or keep it to myself and avoid ever putting myself in a situation like that again, because I feel she will believe me, understand me & forgive me, but I fear her insecurities could destroy her mind and eventually end the relationship.