I mean... As far as I know, as early in our prehistory there shouldn't be any form of civilisation. The Sumerians showed up... What, 2000 years BC? 3000 at the extreme most. So there shouldn't be an Atlantis either.
But there is, so having Rome to exist isn't the worst thing we can do.
EDIT: @Jcton So would our Atlantis actually have conquered lands or colonies?