Not sure how to approach this

I am a guy and I asked a good female friend out who was a lesbian (Not sure if she still is, claimed occasionally she's bi) out to a dance and she agreed to go with me. She is a kind, honest, friendly, intelligent and beautiful person and I'm attracted to her.

Is it worth telling her how I feel sometime in the future?

I appreciate all replies, thank you in advance.

Tell her that you are interested and see what she says. It is the only way to know.

I agree. Go to the dance. Have a good time and ask her if you can take her out again. You don't have to get into the question of sexual orientation unless she brings it up. If you're a nice guy, she might just go with the flow.