I work at an museum too and it seems that even entry level office jobs in our Development, Curatorial and Research departments require a minimum of an MA, which is why I decided to bite the bullet and go for it. I have 3 friends in the museum right now that are currently looking to move up from our hourly entry level positions to an entry level admin job....here's the kicker - 2 have MAs and the other is working on her PhD.
It just seems mind boggling, so I started asking Director level managers what their experience was at other museums and all said the same, the higher the degree the better. For operational jobs (Visitor Services, Security, Gallery Attendants, Event Planning) a BA should be sufficient. We are always filling entry level positions to recent graduates from all over the states so it seems to just be a sign of the times.
But I agree with fullofpink, I would wait until you know for sure which you would like to study. I've worked at the museum for a couple of years now and it really helped to shape the direction of my art studies and is a complete change from the Museum Studies program I originally wanted to do.
I hope this helps!