Wedding or no wedding?

Long story short, my boyfriend and I are getting married at the courthouse on July 29th. The same day of my mom's 50th birthday. Our wedding planned and her birthday isn't yet. When I called her with the news, she just insulted me and put me down like no one ever does. (I have a verbally abusive relationship with my mom...) She told me to cancel my wedding and told me that her birthday was more important. Also, we are expecting, and wanted to get married before the baby arrives. The problem is that  if I want to get married at the courthouse in summer, I'd have to wait another whole year... Is my mother right? That her birthday is more important and that I should back down in order to let her have it her way? Please I need some advice...