Am i wrong? Might be in wrong group.

Am I wrong to not let my dad have anything to do with my 6month old? Im fixing to be 18 an have only got to meet him once. Which was my choice not to see him anymore bc the day I did meet him he was drunk an strung out on dope. My dad's brother is married to Jessica an she is constantly telling me I'm an piece of shit for not wanting to have anything to do with my dad an for not letting him meet his grandchildren (I'm currently pregnant) but when I got to meet him he didn't try an find me I found him an he even told me if I would have never found him he would of never bothered with it. The only one I actually know in his family is my uncle Scott which is his brother an he is more like my dad then my real one. He told me that my dad hasn't changed an still the same as the day I met him. An no one seems to get i don't want that kind of person around my children other then my husband an it's annoying that his family an mine is always saying give your dad a chance he's had almost 18 years of chances.