What did I get myself into?

So I had a "brilliant" idea about a month ago on my way home from work... I want to run a 5K this summer. It was just a passing thought but I made the mistake of telling my darling husband about it. Well it was less than a week later that he came home and told me that his work was running a 5K on May 29 and would pay his entry and so we would just have to pay for me. Why did I agree to this? I haven't exercised 15 times in that last 15 months (don't judge me... I was pregnant) anyway we were going to start last Monday but it rained :) but I knew if I didn't start I never would. My goal for Monday was to run for 10 min with out stopping... and I did 15 min/ 1 mile!! I was so excited. The next day Scott ran with me- 2 miles!!! This Monday we made it to 3 miles, we did that again Wednesday and again today! In the last 12 days I have run 9 times!! I can't believe it! The sad thing is I've gained weight- but I do feel healthier and my waist feels more toned. We didn't run yesterday and I felt like a slacker- so maybe this running thing will actually stick... We'll see.