18.
It certainly made Sabrina a pain in the ass, I'm sure. I mean .... I can't really talk about personal experience because I never actually beat RBY, but I remember trying my best to train my Jolteon for her because it eventually learns Pin Missle and everything else that could have strengths against Sabrina were part-poison. :|b
And knowing the fact that I hate grinding I think I gave up and just tried my best against her lmfao. Because for such a eh move Jolteon learns it at quitea high level (for me anyways) @_@;