After living in Vancouver for 3 years, I finally did the Grouse Grind with a few of my friends! The view is beautiful and I actually heard the sound of grouse (for the first time!) as I was hiking up. As a person who rarely hikes, it took me 1.5 hours and I would say that as long as you have the determination to do it, you can do it. The Grouse Grind is not a super intense hike, you might just need a few extra rest stops than the frequent goers!
Oh yea, don't forget to drop by for the free Lumberjack show on the hill!