Hi, GGHJ! This sounds great! If you two are both ready, I’m sure it will be a beautiful and memorable experience. Are you nervous? Did you have a question? If there’s any erectile disfunction, you can simply address it on the spot (if it even happens at all). If you two love each other and you both want the same thing, whatever happens will occur with love and support. I wish you both the best of luck - I hope your next level is everything you imagined and more.
Why do you think she will have trouble having an erection? If she is aroused she will. However, if she has medical reason for why she may not, that must be considered. Does she have erection problems in general? It's hard to talk about sometimes but you two seem good at conversation so talk about it. If she is taking hormones to feminize herself, that should be considered. https://www.mayoclinic.org/tests-procedures/feminizing-hormone-therapy/about/pac-20385096. (copy/paste that link). They usually block testosterone and add estrogen. A fix for that are the ED drugs such as viagra, cialis, etc. Your friend can talk to her doctor about that. Enjoy. Life is short, live happy.
It has been a while, so here is an update. We (my girlfriend and I) got married. Our love life could not be better. My worries about her a ability to have an erection where unfounded. In fact, it turns out her penis is bigger than mine. A further plus is that she is able to ejaculate. We could be happier!