I'd say the same, a prologue isn't usually seen in a chapter book as far as I know though with middle grade it's fine--but of course with middle grade you'll often be advised to lose the prologue if you can (I'm sure there are threads here about that if you do a search).
That said, if it's a first draft you could also just write the prologue if it helps get into the material, get to the end of the story, and then after having readers give comments and knowing the story better, that's when you could figure out how to drop the prologue for a next draft.