With my aids, I can easily carry on a one-on-one conversation indoors. I can do ok in a small group if we're in a circle. In a classroom setting, I have a hard time hearing people behind me, so if someone asks a question I turn around to see who is talking. I was in Disney World a few weeks ago and heard nothing.
I was in speech therapy in elementary school and apparently speak just fine now. If I could have gone to a Deaf school, I probably would have jumped at the chance. She will learn English from you, from her friends, from TV, etc. She will not learn ASL on her own. In a hearing school she will always stand out because of her aids. However, I think she'd probably do just fine if they are willing to help her out with things that are difficult for her. I remember having an awful time in gym class, just could not hear what I was supposed to be doing with all those darn sneakers making noise. Until she's old enough to tell you what's not working for her, I would go to class a few days with her to try to see trouble spots.
Good luck!
This. This exactly. The world is NOT a soundbooth. We get SO many HOH as kids people saying that they wish they'd gotten exposure to the Deaf World and deaf ed. With ASL, and attending a Deaf School she will have a community and a POSTIVE identity about being dhh. Fitting in can be REALLY important. Instead of being The Girl with the Voice/Hearing Aids, she will just be a girl who is fluent in ASL, and attends a Deaf school, and has a strong powerful positive identity!