Our elementary school had a cheer squad for a few years. They performed at a couple of Flag ceremonies (an every Friday event at our school). But it fizzled out. I think it fizzled because without a sport to cheer for, or competitions to work toward, they really didn't have a purpose and I think the kids lost interest. Other than competition squads which are independent from school, the high school is the only place for a cheer squad around here now.
But for the purposes of fiction - totally doable.