Tile question

[WeezyBengal]

Hey Sunset, got a question for you:

So I am about to begin painting my newly tiled bathroom. First thing I need to fill in dry wall holes. I have filled in small holes before (where screws were in, etc) but there was about a 1/4 inch gap between my tiled shower and the drywall. I had to cut the drywall and install backer board on the wall, hence the gap. Do you think it's OK to just fill the gap with joint compound, sand it, and then just paint over it? I