I need some encouragement and help in the area of exercise. I'm type 2 and have been on insulin since April 07. I've been going to the gym ever since and taking Zumba classes, walking on the treadmill and working on some of the weight machines. I'm increasing weights on the machines and getting better workout results due to that. Also I'm gradually increasing my speed of my walks on the treadmill. When I began I was walking 2.8 mph (slow) and could only last 15 minutes. I've increased now to walking for a solid hour and my speeds have been consistently 3.0 - 3.2. I've increased to 3.4 - 3.6 a few weeks back and this week have increased it to 3.8 - 4.0. At 4.0 I'm at a slow jog.
My first goal is to sign up for a road race as I've never done this. There is a beach race coming up in September and I have a choice between 1 mile or 5k (which I believe is 3.1 miles). On the treadmill I am already walking 3 miles in an hour. But it's walking not running. I'd like to sign up for the 5k and actually run it but am not sure I can. The mile I know I can do but want a challenge, but I don't want to look like a fool if I can't run 3.1 miles.
You have to know that I've lost about 15 lbs recently but still have 85 to go so I'm not a small woman and I'm only 5' 2" so I have short legs as well. Not the sterotypical runner

I wanted to talk to you guys first to see what you think I should do...the 5k or the 1 mile. Any advice you can give is much appreciated.
I just recently got my lab results from my doctor and they are tremendously better (as I talked about in another string). A1c, cholesterol, triglicerides, etc are all mostly perfect now. My doctor says he knows that my exercise over the past 3 months has done that....the insulin and eating right got it started but exercise has made those numbers exceptional. I want to do more and shout the benefits of consistent exercise from the rooftops!