We may be in a simulation, but your odds of being alive to see this (conditioned on being born as a human at some point) aren't that low. Around 7% of all humans ever born are alive today!
You could go back to Lucy and add only a few million. Compared to the billions at this specific instant, it just doesn't make a difference.
Given that we only hit the first billion people in 1804 and the second billion in 1927 it's not all that shocking.
But this is also just the non-intuitiveness of exponential growth which has only now tapering off.