Just a lonely bisexual looking for advice

Basically, I'm in love with a friend (same gender as me) whom I've known for two years now. She lives in the US, I don't. We visit each other a few times a year and do something fun. When we first met, I wasn't starstruck or interested in her, but over time as I fiddled over my sexuality, I realized I was bisexual when I began to fall in love with her. She's had girlfriends in the past and I'm not sure if she's single. But I'm new at basically everything in the relationship world, and will be seeing her soon. She doesn't know how I feel about her and I don't know if I should tell her in case we ruin our friendship. Looking for advice on what I should do. Thanks

Are you looking for sex only (exploring) or for a relationship?

a relationship

I'd tell her you have feelings for her but respect her feelings if she doesn't feel the same way. There may be a cooling off period while you sort yourself if she disagrees with you. I don't think you should be afraid. Friendships come and go. They also evolve. If you cling too hard to something or someone the way it exists now in this time frame, there is really no guarantee it will last that way in the first place. In other words, you both may not even be friends in the future due to other circumstances.

I'd consider the distance and if it doesn't bother you, work things out together. Be realistic that one of you will have to move if it gets serious.

Life is too short to play mind games. Go for it.

Do you think I should tell her before my visit or during? Thanks

Keep in mind that regardless of your sexuality, not all friends are meant to be lovers. When you try to change the dynamics you take some risks. She may take you up on an encounter, she may be involved with someone, she not may be attracted to you, she may see you as a friend, not a lover, etc.

Why not go on the vacation and play it by ear? Rather than come on to her, simply come out to her and take it from there. If she wants an encounter after that fine, if not fine and you preserve the friendship and vacation without awkward moments. In the meantime join some local LGBT groups for support and get on some LGBT dating apps to test the waters locally.

Do you think I should tell her before my visit or during? Thanks

I would also wait until you see each other in person. Enjoy your time together. Just remember it's not the end of the world if things don't go according to plan. There are plenty of other people to meet.