Micah is not grown. He's not even financially independent. Has he ever had a part-time job? I did not get the impression he received a full scholarship which means his tuition and expenses will be on his parents' dime. The fact Micah curated a separate secret list of schools was dishonest and deceitful. At the very least, Micah should have discussed his thoughts with his parents. As a compromise, he could have tried Harvard for a year then transferred out.
His decision was made from a place of privilege. Illustrates being 18 makes you a legal adult but the maturity takes time.
Of course, we know the character is attending Xavier so he can continue to be part of the show rather than the odd drop-in like his pops. I'm glad he's sticking around.
I agree, Nova can kick rocks. I wish they'd extended Nova's redemption arc and made her put in more work to earn her family's trust.