(Let's try this again!!!)

Tiff is Kirby's adoptive mother from the FUTURE where Kirby is.... still her adopted son, and Tiff is grown up! Tiff is 20 years old.

(I hate it when people ruin stuff that's meant to be wholesome. Can't create the Canon Tiff from "Kirby right back at ya" because some pervert will ruin it. So this is as close to the original as can get.)