The only reason I wouldn't do it is if she might struggle, sounds like that is far from the case.

ex: We had an opportunity for dd to move up one grade level, however we found out she had vision issues so we didn't go for it, wanted her to catch up ...and it has been an ok decision, some serious boredom, but not feeling underwater in reading at the time was good. Now she is sailing way past 'above grade level'...so we'll see what occurs in future.