The Degrassi High guide to legalizing weed. Cannabis continues its crawl to legalization in about a year, while potential players continue to line up marketing strategies. Now here’s a piece from Rebecca Haines-Saah, who played the surly “Kathleen” on the original Degrassi (she's now a health professor at the University of Calgary) advocating for 18 to be the legal age for buying marijuana, based partly on her past experiences: