I'm a December baby and was always younger than my class. There were some good things and bad.
With a girl there's less worry about maturing as with a boy and when they wanted my son to skip 1st grade, I said "no". They have Talented and Gifted classes in middle school here and AP classes in HS. He was fine taking those.
Personally, I wouldn't do it now. If she's meant to skip, she can do it later on when you see more how she reacts to a longer school day. Just keep her mind busy
