Pro's and Con's of changing my surname?

Wait, because you have a chance to be a better person.
Don't give him that power over you - you are part of a larger family than just that guy. He is an individual, and so are you - and if he isn't a mass murderer, the name isn't what is going to link you to him. Just go be a better person. Someday, you also may find there were underlying reasons he didn't do what he should have done, and there may be time to forgive. When you're young, there is a lot you don't know about your parents, that you may someday find out. Just keep it - you're not going to outrun it, but you can out-achieve it.

you'll be 18 so i would do what you want and if they dont like it thats their problem