Is it normal that i might fancy my friend?

Hello. I'm a girl, and i've got a friend (also a girl) which is about my age and she goes to the same school as I do.
I've known her for about a year and I feel like we've become best friends now. I can talk to her about anything.
But sometimes, it feels like we're so close, that its not even like friends anymore. We kinda joke about it, but I'm not sure if I like her as more than a friend, or not.
A while ago, we were in a very good mood and we were making all jokes and stuff. But suddenly, she said that she's been in love with me for a long time. When I didn't respond immediately she quickly said it was a joke and said she's in love with her boyfriend (yes, she has one.) and tried to change the subject quickly. But now I'm not sure if there might have been truth in that thing she said, or if it was really just a joke. But that's not the only thing though, a while ago I also said something I found cute about her, the way she laughs. And she said that she really had to blush after I told her that.
Now, i don't know if I like her, nor if she likes me. She does say she might be bisexual but isn't completely sure about it.
The boyfriend she has is just a guy she knows now for a few weeks or so, and they're only dating for about two weeks now. So I dunno if they will stay together or not.
Anyways, do you think she likes me more than a friend and what should I do? Should I ask her or tell her that I kinda fancy her? I'm afraid to ruin our friendship but i just feel this way... I dont know if i'm hetero or bi either. I just feel very comfortable and also sometimes blush or get this ''butterfly'' feeling in my stomach when I talk to her.
what can i do?

plz.. help me!