When I was pregnant with my first I went out every Friday throughout my whole pregnancy to a goth/industrial club night (my partner is a DJ, it's where we met and most of our friends go there too so it was my best social opportunity) and once I started feeling those little wiggles it was funny how much he danced to the music! I did stay away from the speakers though, didn't want it to be TOO terribly loud for his developing ears... he's three now and has great taste in music.
Baby will like it as long as you are enjoying it. I listen to loud jungle and drum & bass in the car. Your mom is just saying that because she doesnt like it.