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.
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.