i went to physical high school all 4 years, so i really can't weigh in on that, but i can weigh in on the skills it takes for online learning.
My freshman and sophomore year of college, i was on campus in classes mon-fri. my junior and senior years, i took as many online classes as possible to "free up" my time so that i was still able to work (for money) and intern (for no money). Attending class mon-fri didn't really allow for this. so while i technically freed up my schedule, i really didn't. luckily, i had all of those qualities
12stepCheermom listed. you truly will be teaching yourself everything. sure, there's ways to get help, but it's all on you. if you have time management issues now, you'll only need to manage your time even more wisely when you are responsible for your own education.
getting into college is something very important to consider as well. I recently saw first hand an example of why you'd want to go to a physical campus school: at my job, there were two awesome candidates up for a job opening. they both had master's degrees in the same field. one was from college with a campus and the other was from Walden (completely online college.) the one with the "real" (i know, both are real) degree got the job. as much as it shouldn't, the online degree makes people look at you differently. when i asked the CEO why he chose one over the other, while there were other reasons too, he said the difference in degrees made a huge difference.
now i don't know you or your circumstances, so this is just some friendly advice: if i were you i would either: 1.cut back to one cheer team. use those extra hours to devote to school. or 2. give up the dance team. i don't know the circumstances, but i know you mentioned you aren't actually dancing on the team currently. so quit. normally, i don't advocate quitting, but school comes first in my world. period.
i know it's not an easy decision, so i truly wish you the best... and while it's hard for most of us to admit, when it comes down to it, it's only cheerleading.