Could anyone give me any advice? I'm not sure what to do

Hello

I've had a ''crush'' on this girl for a while now, about two years I'd say.
I really like her.

Nothing happened between us but about a year ago we started hanging out at weekends going climbing etc. She has a girlfriend and I don't want to get in the way of their relationship. I don't want to be that person.

I worked in France for the summer and to be honest I thought we would just drift apart, but we spoke quite a bit and planned a few climbing trips before she went to uni.

Once I returned it started to become obvious that there was some chemistry between us, again I'm not up for getting involved in messing their relationship up. I like spending time with her though, even if it is just for an hour of climbing.

I went on a night out with her about a month ago and it's now pretty obvious that we're into each other, we almost kissed in the club but thankfully someone interrupted.

We've been speaking a lot and I'm going back down in two weeks, not just for her but a few of my friends are having a night out.

I really like her. I know something's going to happen.

Do I tell her how I actually feel and leave it with her? Or do I just hope that nothing happens.

Sorry if I haven't explained this very well, oh and thanks for reading!