There seems to be some disagreement about the use of prologues. What qualifies as a prologue? If a first chapter covers an event that happens a few months before the next scene, is it a prologue or a first chapter?
Prologues go in and out of fashion. Some publishers like them, others hate them. Some might call their prologues Chapter One, but they're still a prologue.
Currently, prologues are out of favor. But this is my opinion: A good prologue that is well written adds to the story. The main purpose of a prologue is to give us needed backstory, but to allow it to happen in real time instead of the dreaded info dump. Prologues work best in fantasy, where we need to know something about the main character or the villian, but the main action of the story doesn't start until the main character comes of age. Or sometimes a thriller, where the bad guy does something to set the story in motion, but the effects of his acts aren't felt until months or years later.
Here's an article on prologues that explains it pretty well.
None of this info really helps you decide whether to call your prologue a prologue or to call it chapter one. If you're really concerned about it, go look at some books in your genre from the publisher you're submitting to. Do any of those books have prologues? If so, you're fine using one. If not, call it chapter one.