<human>: Can you give me the gist of the text in a nutshell?

As the title says, I [20M] need a little advice...with a girl [21F]

Basically she is the ex of a friend of mine which makes it a bit complicated I guess and I don't want to 'betray' our friendship. They broke up more than 2 years ago and he already moved on with an other girl shortly after (2 weeks after...) We all went to the same school together but it is after we went to different universities I started talking to her. Almost 1,5 years ago. We became some sort of friends with benefits. She was the first person I ever had sex with. My friends found out about the fact that I had sex, because she left me a big ass hickey in my neck...and because I had an even bigger smile on my face. This was more than a year ago and I still haven't told them who I slept with. Nobody knows. 

She told me in the beginning that she really liked me and that she actually prefered not to be FWB's. Back then I just wanted to have sex with someone. Now, more then a year later, I think I'm totally crazy about this girl. I started to really like her. She might not be the most beautiful girl in the world, but she is to me. We get along really well. And she's crazy (in a good way) which I really love. She's funny, playfull, adventurous, cute,...

The problem is that I don't know how to handle this best. I don't want to lose my friends but I also don't wanna lose this girl because I think she is getting tired of this. This and the fact that I care a lot what other people say/think about me is why I haven't asked her yet if she wants to be my girlfriend.

Sorry for grammar mistakes or a bad layout. I made this post on my phone.
<bot>: I love my friend his ex but I'm afraid I'll lose my friend(s) when I ask her out.