Where did those rules come from, do they still exist?
The scoring system was changed in the early 2000's to be best of 5 or best of 7 games to 11 points, in order accommodate television audiences and hopefully make for more exciting games. Whether the move was successful is still debated by many players.
There are few official competitions using the old scoring system these days - I think the classic hardbat competitions in the USA still play to 21, as to some 44mm ball competitions in Japan. And of course probably millions of people who are still using the old scoring system at home, just like you!
Here's a link to the new ping-pong scoring system, if you feel like getting up to date, or entering any local competitions.