Is my mom out of control? Or am I rude?

OK so my sister is graduating from her masters this year and my mom wants to have this dinner in a place over an hour out of the city. This wouldn't be a big deal but I have a baby, who needs to be in bed by 7 or she cries and whines, then screams and then wakes up a ton when she finally goes to bed for the night. This means that dinner would be ruined for everyone in the restaurant and the drive back would be absolute torture for us (we can't stay overnight because we have dogs and don't have money for a hotel). Anyways, I explained this to my mom, who said OK, and that we could do something else another day then. Fast forward a week and she comes to my house and tells me that these are the plans and that's all we are doing, and that if I don't come I'm selfish and rude. She tells me my husband needs to get the time off work and that she knows his manager and can speak to him to get him the time off. I told her no and explained again and also told her that my husband can't get time off (he's working and in school and barely has time to do school work or study or anything else) and he's going to have to take time off for his finals coming up. She then says she needs to ask my husband himself and tries to get him to take time off and says he can stay with the baby and I can go, as if I don't have a say in the matter. I'm at the point where I'm so mad that she refuses to listen to me and thinks she can make decisions for me. Anyways, am I selfish? Or is my mom being out of control? And what would you do?

Thanks for all the comments! I will definitely speak to my sister and explain why we won't be there and see if we can do something together another day. To those saying I should get a babysitter, my mom is usually our babysitter, and my husband can't get time off work because he needs to take time off in a couple weeks for exams, so they won't give him the time. My biggest frustration is that my mom doesn't take no for an answer, she just keeps pushing and trying to force me to make a different decision, but I am trying to do what's best for my baby and ultimately my family. Thanks again!