I did it, I finished my first run! I did the Scotiabank Toronto Waterfront 5K in 42 minutes, doing intervals of two minutes of walking and five minutes of running. It was a good pace, fairly challenging but not so hard that I felt like I wasn't going to make it.
It was cool to run in a real race, although there was a marked difference between the 5K and the "real" races; we had little kids, people with special needs, people who clearly intended to amble the route (not that there's anything wrong with a nice amble, but I'm not sure I'd choose Lakeshore for it). There was even a woman enjoying a nice, bracing cigarette before the race began! But hey, it was a good start and I'm really glad I did it.