Dad trying to come into the picture

Ok so I need people’s advice who have been through this before. My dad texted me on facebook I never met him in my life or anything, he said he wants to get to know me and stuff. I’m not sure what to do or how to respond. He has a tattoo of my name on him and pictures of me. I can’t talk to my mom about it since she passed away. I also have a sister who wants to meet me and honestly I was excited at first but now I don’t really want to. (my dad doesn’t talk to her but her mom got in contact with me) I would like to get to know my dad but my sister and her mom keep saying negative things about him so it’s making me not want to meet them but I also feel bad about it. Any advice on how to handle these things?