The so called "facts" were actually fake. The matchmaker starts visiting around 7 and has been reported to visit at least till your tamagotchi turns into an old timer. Once it does, please don't expect the matchmaker. If you do, you will end up mate-less
You will definitely have to be patient - the matchmaker doesn't visit every time at the starting age when the matchmaker can come. It is probably from 8-9 for the most common visits.