I had to wait a few days to make sure it wasn't a fluke, but it seems clear now. I am not a penguin anymore.
In the running community on-line a penguin is someone whose running pace is closer to a waddle than to a sprint. Generally a pace slower than 10 minutes per mile puts you in the penguin category.
My first week of running was those Couch-to-5k walk-run intervals (2 minutes running, 1 minute walking, that sort of thing) and my pace was around 13 minutes per mile. Waddle waddle. By the time I had eliminated the walk intervals I had sped up a good bit, to about 11.5 minutes per mile.
For the last three weeks I've been trying to increase both my speed and my distance, hoping to graduate from penguinhood. I've added 3 km (2 miles) to my distance, and my speed has been coming along gradually. Within the last week my faster flatter runs have hovered right around that 10-minute pace. Was I still a penguin? I wasn't sure. A few seconds this way or that, a few missing metres could make the difference either way.
But today I definitively discarded my penguin status, pulling off a 9:55 pace on my 3-mile (5 km) hill route. I'm sure of the time and distance on this one, and with an elevation gain on the outgoing leg of almost 100 metres, this route isn't a casual stroll. So there you have it. I run. I no longer waddle. And, best news of all, the dog is occasionally breaking into a lope, and panting alongside me, tongue lolling and finally looking like she's getting a workout too.