If i think back to the time when i did my OW course the first thing the instructor did was to get us to put our faces in the water, it was weird, and i felt very nervous. After a few minutes we got to totally submerge ourselves. We only went down about 2m but could really feel the pressure in the ears.
Breathing under water is really strange and takes some getting used to, once you get over the initial fear and shock it is pretty cool. I think you either love it or you hate it.