PLEASE NEED ADVICE AND OPINIONS ASAP!!

Okay, so on Friday my Doctor called me and told me I urgently needed to come in to see him today to discuss some findings he seen on my anatomy ultrasound I had on the 18th. I came in, and he informed me that there was numerous abnormalities he found on my daughters ultrasound. He said that she has what he believes is omphalocele and that her ventricles in her brain were enlarged. He referred me to a genetic counselor and to have a level 2 ultrasound done immediately, and got me an appointment for Monday. It requires me to a hospital that is in Dayton (around a hour and a half away from me). I do not like to drive, especially that far by myself and my husband has a chance of not being able to get off work because of how short notice it is. I asked my sister if she could take me, and she gladly agreed. After I told my mom about the condition my baby girl was in, she said she was crying all night at work so dramatically that her co workers told her she needed to come home. I understand that this is her grand baby and she’s concerned, but my mother is very very dramatic and emotional. I want my sister to take me because I need to be able to speak to and listen to the doctor without the distraction of other people’s emotions, which I know my sister is capable of. Don’t get me wrong, I love my mom to death and I appreciate that she wants to be there and support me, but I just really wanted it to be my sister and I, and of course my husband if he is able. I woke up this morning to this text from my mom literally inviting herself to my appointment and telling me if my sister still wants to go as well, that she can. Am I being shitty because this upsets me a little? How do I tell her I just want it to be us at the doctors without hurting her? (My mom really takes things dramatically and she’s always babied me and treated me like I am still a child. She is very emotional and takes things to the next level when it comes to me, and not my sister who is also pregnant and not her biological mother, they’ve also never really gotten along because of this) I need help and opinions! Am I wrong and being a shitty daughter?