Mothers! Would you be acting this way towards your daughter's boyfriend?

Get over it. Ever heard the term "monster in law" ? Sometimes parents just don't like you for no reason at all. It might be somehting you did once or they heard about you, or they just might not like you dating their daughter, who knows. Either ignore her or tell her that you don't know why shes acting so hostile to you, but you care about her daughter and would never do anything to hurt her. You guys are 19, it's not like you have to obey by all of your parents rules anymore.