Hi! Scooterfag checking in!
What scooter is it? The most important question is whether it's a two stroke or a four stroke. A two stroke has about 3 moving parts and a whole engine rebuild can be done in an afternoon in most cases. A four stroke is more finnicky and honestly I wouldn't put my daughter on a 50cc four stroke, you're looking at 3hp at most, it's flat out dangerous on the roads. A derestricted two stroke will hit 50ish mph and accelerate a lot quicker, much safer.