Oh okay, Mexico level should be at least 1-2 cats lower than Argentina, a 3rd should be a 5th. Achieving a 5th category level in 6 months with a tennis background and that much training is not that crazy, so I believe you.
Now, that is not high advanced level, it's advance intermediate. Semi pro players are not close to that level, they are much much further.
I play 3rd/4th in Argentina (more 4th than 3rd) and the players from 2nd, which are not even in semi pro territory, that I sometimes play against can defeat me while playing at 60% of their potential.