Straight but curious?? Help!! 😱

So I know I'm not the only one, but I'm pretty sure I'm straight but I've always wondered and want to try with a girl.

I've been friends with benefits with this guy for a few months and I told him that I'm curious about it so he suggested a threesome. I am excited for but but at the same time nervous. I don't know what to expect with a girl.

I don't know if I can finger a girl because I personally don't like doing it myself. It's just I'm not used to it. How do I eat a girl out? What should I do?

I'm scared that when I have a pussy in front of me I don't know what to do or back out because I'm not exactly bisexual.

Any advice for me please?