Very good for first year 8u. Let her play and make adjustments when necessary.
That is a very good swing for an 8 year old. The bat does appear to be a little heavy for her. I noticed 2 things. She gets taller as she comes into contact. Stands up a little, comes out of her posture early or what ever you want to call it. Also, the "box" gets a little over stretched (elbows to close to each other)
Over all she has a very good foundation and she coils(loads). This is way better than the average 8 year old. I am surprised she only made 3rd string team.