21 (both from birth and from conception)
That's a bit superfluous if you're giving an age in year(s). It's always going to be the same unless you're rounding up, or maybe if you're an alien who gestates for twice as long as a human
With that, I don't think I've ever seen anyone casually mention their age since conception for this kind of question before.
If you're born in January or February, you were likely conceived the year before.
I've already reached the quarter-century mark by such logic.
Alas, I'm but 24 by the rest.
Poll
