I guess my suggestion would be to ask her.
Let her know that you really want her to come and that you need some help figuring out how she will get in.
As far as actually getting in, a lot depends on the exact set up of your two steps. She's possibly dealt with the same type of situation before.
My DD is small (for a young adult) and between my DH and I or my other DD and I, we can usually get her in someplace if it's only 2 steps. Someone larger or with a heavier wheelchair would have more problem (and we would if we brought her power wheelchair). Your new friend might possibly have a portable ramp. Anyone who lives in a wheelchair expects that most people do not have accessible homes. I think that she will appreciate a new friend who is making an effort to try to make her feel so welcome.
Hopefully, you'll get some other ideas.
There were so many spelling mistakes on this, I just had to edit it (so much for typing after midnight in a dark room).