I don’t believe that kind of time travel is possible. But, if it were possible, the odds of finding that exact individual (who probably didn’t actually exist) at that exact time are so minuscule that for all practical purposes, it may as well be impossible. But, if that were also possible, it did happen, and that was the only thing that happened differently, then I’m thinking the most likely outcome is that evolution would pretty much continue on the same course, probably even with humans eventually evolving.
It’s common to think of the evolutionary process in a more or less linear fashion that could theoretically be traced back to a figurative Adam and Eve, but the reality is, it’s so much more messy and convoluted than that. Evolution is a culmination of many factors such as the environmental conditions and populations that exist during a given time frame. So even if there was one specific common ancestral individual who happened to live at the exact time the dinosaurs were alive, which that individual is not a thing that existed, there would almost certainly still be a population of others of the same species living in the same conditions – so theoretically would still ultimately lead to the same evolutionary outcomes in most instances.
So, I think it’s very possible people would still exist. But, it wouldn’t be the exact same people, living the exact same lives, at the exact same time as now.
On the other hand, who is to say that the common ancestor hadn’t already produced the offspring that specifically lead to you and I being born before it was eaten? Who’s to say that individual getting scared and eaten wouldn’t have happened anyway, regardless of whether you were there or not? Who’s to say that wasn’t actually the defining moment that ultimately resulted in the evolution of people (and you and I specifically)?
I dunno, this is all getting a little too timey-wimey for me.