As a girl who is named Saturn, I'd say if you really think it's pretty, you should go for it. *I* was never teased in school, and I always get compliments on my name! I think it's a pretty name, and it's unique and pretty cool. I've been living with it for almost 14 years and it's an amazing name!
This would sound ridiculous on a real person, but not as bad as Jupiter, Venus, or especially Uranus. Nevertheless, it still looks silly, considering it's the name of a car.
It may seem like a cool idea, but when you think about the reaction other kids would have to it in school, well, it just doesn't seem worth the risk. This sounds more like a pseudonym for someone in showbiz, and a bad one at that. Planet names are weird on people.