FB can be a good thing, but it can be bad to. It does invade ur privacy, if u want it to. if u decide to tell everyone everything. it may backfire if u make someone angry. I tell u 2 stories about some people in my town.
1st story. My GF ran a photography studio. Unfortunately it was illegal as the person sub lettting wasn't allowed to rent out the space. He then tried to hold her Camara lightning, backdrops, PC, Printer for ransom. But me knowing a few people walked in and got her stuff back. Next thing he decided to post allsorts of lies on FB ruining her reputation, therefore destroying her business.
2nd story. this is an extreme case btw. Basically this person made an enemy. This person then put the good person on the police informants list, then he posted it on FB. The good guy was then shot and killed.
Its all how u use it. but tbh i think someone as young as 10 shouldn't have a FB page. Firstly security reasons, secondly if u do say something wrong or make enemies. it could have consequencies. So ur parents are right in a way, it can ruin ur future. But as i said. It all depends how u use it.