Teen pregnancy

I'm 17 and pregnant,it obviously was not planned. My parents are on a holiday and I have my first scan appointment and everything else on Friday. My boyfriends mam wants to come with me and my boyfriend to this,but I don't want her to come cause she is really controlling and she will want things her way,and she will embarrass me in front of the doctor or the midwife. I really don't want her to come and my boyfriend is too scared to saying it to her. I don't know what to do,will I just go without my boyfriend and then maybe she won't come?