I like my best friend.. Advice?

I *think* this is the right category.... Anyway I've started liking my best friend recently. (We are both girls) She's bi and everyone knows but I'm demisexual and haven't told anyone. So she has a boyfriend but he doesn't really like her anymore I think.. They don't ever talk and he just ignores her. Now my crush has been holding my Hand a lot. Good sign I guess? But I don't know if I should tell her I like her. He may already have a hint cause I like holding her hand, but I don't know... Any advice please?? By the way, I've never liked another girl before.

Hi there
I'm myself pansexual, and have been with girls before (I'm now in a relationship with a guy) and well, I don't think there is much difference between being with a girl or a boy or anyone of any other gender. Is this something you dread ?

I'm not sure to understand what kind of advices you're seeking here : how to tell her you're in love with her ? How to deal with the fact that you're now feeling more than just "great friendship" for her ?
Are you afraid telling her what you feel would put an end to your relationship ?
You can try to get some clues about what she feels... How she's doing with her actual boyfriend, if she's happy with him or not... Tell her you care, sending some clues yourself, I dunno..