Everyone holds in their pee every now and then. And that's okay! Just don't do it too often, or it could lead to some serious problems down the road.
Peeing is pretty important. Your kidneys filter excess water and waste out of your blood and that urine needs somewhere to go: your bladder. Normally, it’ll hold 1-2 cups comfortably. But if you make a habit of holding your pee for long periods of time, you can actually stretch your bladder to easily hold even more.