Also, have you checked with CSU to see if they have any flexibility re the age requirements?
Not super recently but I did give a call to the community college this morning. She more than meets their low requirements to waive the age limit to enroll. You only need something like 19s on the math, english, and reading parts of the ACT to be allowed to enroll in whatever you want. We would, unfortunately, have to pay full tuition at the community college if we just take her out and have her do an online high school or homeschool. If she's enrolled in the local school district, they pay the cost of the CC tuition. I don't see how she'd possibly be able to take CC classes in addition to what she's already doing there, though, and it's not an option to replace classes they offer at the high school, just to take classes that are not offered at the high school.
