Need advice for sex problems / low libido / relationship

Hi,
I am 21 years old and writing this because I really don´t know what else to do and maybe someone can help me in whatever way or has some kind of advice for me. Or maybe it´s just good for me to write it down once. I know it´s embarrassing considering my age, but I have never kissed anyone or had sex. I had the opportunity, but I chose not to because I felt that something was wrong with me sexually, but I don’t really understand what exactly. I think that my sex drive / libido is too low and I don’t know how to fix that. Because of that I am really afraid to have sex / try to have sex because I expect to fail really badly and I don’t want to do that to myself and more importantly to my partner.
But I don’t think that I am asexual for a few reasons. I masturbate, I used to watch porn and I always generally wanted to have sex. Nonetheless I feel that something is off, I just don’t really have a strong desire to have sex even when I am close to a girl I like. And as I said I am too afraid to just try it out, I fear that I might have problems with maintaining an erection or just being bad at it. I feel like that would be unfair to my partner.
I have stopped watching porn completely 5 months ago and although I feel like that helped a little, it´s not a steady process. Maybe I just need to wait longer and it will help me to get my libido back, who knows. Also I got my hormones checked like testosterone etc and everything was fine, I really hoped that that was just my problem. I could have dealt with that I guess.
Because of those problems I decided not to date anyone, because I don’t want to embarrass myself and I don’t want to make my problems the problems of someone else, especially when I really care about that person. I would really like to be in a relationship, but I feel like I cant before I have fixed these problems.
I have a female friend (who studies in a different city), who I have texted with for more than a year and slowly we have gotten closer, spent more time together, did little daytrips together etc. I really care about her. We started to hang out at my place and started cuddling which I really enjoyed and couldn’t say no to. Eventually she confessed to me that she had feelings for me, but doesn’t expect anything from me and that she feels that she is not really ready for a relationship because she has a few issues she needs to work on, she just wanted me to know. I told her that I am not ready for a relationship as well and that I feel that I would make her unhappy in the long run, and I never wanted that. So we decided not to change things between us, but we have grown closer since. This was 2 months ago. We even went on a short vacation together and had a great time.

Yesterday she asked me what my boundaries are on physical contact because she wants more and so I was forced to talk about some of problems (not very much in detail) which was very hard for me. She was very understanding and said that how things are is fine for now, but long term she wants / needs more (sex). I understand that and I don’t hold that against her at all, that’s normal, I am just the one with a problem. I told her that I don’t want to be a problem for her and that I can understand that / know that, and that I don’t want to be in her way.
So things haven’t really changed all that much for us in a way, but its really hard for me. I cried all day. I want to be with her, I want to want to have sex with her, I want more desire but I don’t know how. Its like watching a car accident in slow motion. Although we are not in relationship, we are more than friends. At the same time, I am just not enough for her, the way I am at the moment. And in a few weeks months, she will find someone who is and that’s good for her, but then she wont talk to me any more and it will make me extremely sad. I am pretty certain that’s how things will play out, but I decided to enjoy the time I have with her as much as I can and when she leaves me, I wont be mad at her and take my time to process that and grieve. But its really hard for me.
I have trouble talking about all of this, but I hope that someone has advice for me, what I could do. Maybe I am missing something. Thanks for reading, have a nice day.