My dad's wants visitation rights after 12 years. Should I be excited or mad?

It just depends on how you feel about him. I haven't seen or spoken to my father in about 12 years, the same as you, and if he tried to contact me I wouldn't speak to him. Too much time has gone by and I feel like I wouldn't even know him anymore, besides the fact that he treated my mother like dirt. My kids don't even know he exists, so I wouldn't allow him into their lives either.

Depends on why he what's to visit now, and also why he did not visit before. Often there are many reasons children do not know or are even told lies.

I will give you an example of my two boys, I went down to see them ( I had court ordered visitation, but they lived in another state, and their mom just refused, if I walked onto her property, she called the police to arrest me for trespassing.) I would send Christmas gifts and she would repackage them with her name as the given. So my boys were in their teens and believed I never sent any money, believed I did not want to visit. But that was a lie. I am not saying this is your case but it does happen.

Also he may have found religion, or just realised what he is missing.