I don't fully understand it, something got lost in translation, but the spirit is there which makes it really funny to me. I looked it up and there's a saying that goes, "Fuck your family back 18 generations" so it might be that fuck got mistranslated or censored into greet. I also wondered if it meant, like, "I'm used to dealing with his type." The way it came out makes it sound like she's some kind of immortal being, like, "I witnessed your great-grandfather's birth, loser" which would be a really funny flex.

Either way, it's like, "I didn't quite get that, but hell yeah sis!"