The matchmaker comes when your tama is around 6-7 years old, she will come 3 times a day for 3or 4 days so there's no chance you're going to miss her ^_^
When Mrs. Busylady (matchmaker) came to my tamagotchi, she was an Adult. She was at four years. I think these ppl are trying to basicly tell you that she comes when you're tamagotchis an Adult. Any day, and hour sharp ( 10:00 , 12:00, etc.) You never know when the matchmaker will arrive- every tamagotchi is different.