You shouldn't get more that a few drops of water in your mouth. Usually from the mouthpiece hanging in the water before you put it in your mouth.
Not to be judgemental, but if you feel you are getting a significant amount of water in your mouth then: 1) you are being hypersensitive to the sensation. Or, 2) you are not keeping the mouthpiece securely in your mouth. Or, 3) You have a leak in your regulator. (Usually, a pinhole in the mouth piece, or a tie-wrap that is missing or loose, or the exhaust Tee flapper valve is worn out or contaminated with salt or sand. On rare occasions, it can be a pin hole in the diaphram.)
Also, it's not that uncommon for new divers to swallow more water than normal. But it usually happens at the surface.