Annora -
I'm sorry to hear about your daughter and I'd imagine that both you and she are pretty freaked out at this point, but things will be okay. We have some young patients on the Forum, so you aren't alone.
The possible side-effects of surgery are scary, but there are some wonderful outcomes. I had surgery myself in May 2007, and while I was a lot older than your daughter (45 1/2), my outcome was very good. My only lasting side-effect is SSD (single-sided deafness) and I have a BAHA implant that helps me with that issue.
First and foremost, I suggest you contact the ANA for their informational literature. You'll find it very helpful and easy to read. I personally think it's invaluable.
You say your daughter has seen a neurosurgeon, but I'd also like to recommend that she see a doctor who treats ANs with radiation - gamma knife or cyber knife - if her AN is small enough to warrant it. The usual threshold for radiating ANs is 3 cms.
If you tell us what part of the country you are from, someone on the Forum may be able to suggest a doctor or doctors for you and your daughter to consult with.
Please feel free to ask us anything; it's part of what we're here for.
Best,
Jan