The doctors are afraid if surgically removed, it may return as a higher grade tumor.
First, I want to say I'm so sorry to hear of all you've been going through. I know you put this post up a long time ago, but because no one has responded I thought at least make a few comments/suggestions.
How was your daughter diagnoses? MRIs are commonly used, but it can be difficult to know for sure what type of lesion is present. Did she have any kind of a biopsy? Any PET or MRS?
Grade 2 is by definition slow-growing, and therefore not cancerous. There is some debate about the appropriate use of surgery, radiation, and chemo. Who do you have as doctors? A neurologist? A neurosurgeon? I hope you are collaborating with more than one, not just an oncologist. Really, chemo is uncommonly used at the initial diagnosis of grade 2, especially if no biopsy first confirmed the nature of the tumor.
The good news is that she is still young, which improves the prognosis. It's hard to know how it will progress, but first it's important to verify what you're dealing with.