To my knowledge, code does not specify how high an outlet should be. For example in apartments designed for elderly people, outlets are sometimes mounted higher up so they don't need to bend down to plug something in.
So far as a bathroom, you could have an outlet for vacuuming or whatever and that could be on a wall at the same height as other outlets in the house. Or if in an area with a mirror, then high up so easy to plug in shavers, hair dryers, etc. Or if for an electric toilet or electric bidet seat and mounted behind the toilet, then mounted exceptionally low so the toilet tank will not be blocking it (get toilet first and see what will work).
In general bathrooms are required to have GFCI outlets and be on their own 20 amp circuit. This is for those power hog hair dryers. Sounds like you may not have that though? Anyway check with your local electrical inspector as to what is required. They are the final word on everything!