The 100K years timeframe is more believable than a random cutoff 12K years B.C. Humans are way too advanced species to progress from monkeys to what we are now in just a few thousand years. I'd say it's taken close to 18 millions years since humans were advanced monkeys, but even then the difference between a "regular monkey" and an "advanced monkey that can make tools for hunting" is massive and needs an extended period of prehistory.