You've received great advice already. I'll just add two things:
1) You may wish to learn all you can on the subject of
underachievement, especially:
- how underachievement may develop when there's not a challenge worthy of one's potential,
- brain changes which may occur,
- the difficulty in reversing underachievement.
2) You may wish to become familiar with the concept of developing a
growth mindset.
If whole grade acceleration is contemplated at some point in the future, you may wish to be aware of the Iowa Acceleration Scale (
IAS) and supporting
research.