Darling Faithy
I feel saintlike
Faith's birthday is December 14th, 1980. By the time Buffy was going through her Crucimentium, Faith would've already had hers, but according to Go Ask Malice [of which I'm referring to because it's really the only source we have regarding Faith's background and upbringing] Faith found out about the test before her Watcher was able to administer it, which makes a lot of sense.
I thought Faith's birthday was dec. 1982. Making her younger than Buffy, like in Faith,Hope,and Trick Buffy said something pertaining to Faith being younger. And I thought it meant in the series, that Faith was only 16 whens he met the scoobies for the first time.