Dunno... it seems possible to have met them by 19, because that would include all school up to the first year of college. If you stay in the town you grew up, chances are pretty good that at some point you might run into that awkward girl from 7th grade who has suddenly gotten really atractive, strike up a conversation, and... Doesn't say that you are dating the future spouse by 19, just met them.
Anyway, don't think I'm gonna fit this mold.