In our case, MS was a little bit of a challenge, but that was largely due to how little time DD(now)14 spent there. For us, MS is grades 6, 7, and 8. Our DD skipped from 5th to 7th, and between adjusting to a little more rigor, a new daily schedule, being in a school over 10 times larger than her elementary, and being bumped into accelerated math, she was somewhat challenged. The next year she started her days at the HS, and took three classes for HS credit. Those three classes were the bulk of her challenge. Your DDs MS sounds like it might be more rigorous than my DDs, so you may not need go our route of doing 3 years of MS in 1.5 years of attending MS classes.
HS has been hit or miss on challenges. Some classes she gets a little bit of a challenge, other classes are complete cake walks. The electives do will give your DD more opportunity to take classes in her interests.
Our DD did do a CTY Intensive Studies Neuroscience class last summer and had an absolute blast - both socially and academically. She's going back again this year.
Best of luck,
--S.F.
