Baby name dilemma

Where to begin... oi. How do people do this all the time?!? My husband and I chose the name Vance 6-7 years ago if we ever had a boy.. we love it! It's different and for short we liked Van. Perfect right? Wrong!! My mom has been so, incredibly opinionated about the name saying it's horrible and she will refuse to call the baby by the name if that's what we choose. Our gender reveal is this weekend and she's ruining my excitement that it is... in fact a boy... but nobody knows yet. I actually can't deal with how passionate and aggressive she's being about the name we've chosen and I'm really stressed about it all. She suggested we name the baby Hamish or Angus because she is Scottish and so is my husbands dad but I don't want those names and we are pretty set on Vance. What would you do?!