Interior dimensions don't necessarily correspond with exterior dimensions (as my midwife always said, because I have slim hips but big babies) so first, don't borrow trouble, it may be a good fit.
I disagree with the advice to get her off first - get her close, edge her a couple of times but girls can conk out after O, we aren't all multiple, and also it can be frustrating even if you are, because you get so close then the guy cums but will not get you off again! So that is something to talk about, we don't all work the same way. But in general it's getting really turned on that creates the space inside (tenting) not the actually getting off.
I hope y'all have a great time.
Perceptive people! So intuitively aware of their surroundings and somehow not quite part of them. I get this.