I think you already know the answer.
Plus as already stated, get her a couple of lessons from a FFF member.
What is her height?
If she is short a rod of 8 1/2' 5 or 6 wt would be ok, but average would be 9'.
The lady i tought to fish uses a 9' 6wt Sage XP, but started out with a 9' middle to tip action Orvis, she is about 5'4''.
Don't spend a fortune on her first rod, unless you really really love her!!