I took a peek in my Endomondo data. I have logged my runs since the very beginning of my mid age running attempt.
Previous history
I have never run, except for a few months when I was around age 18. I have always hated walking. Car, train or bicycle was my means of transportation. I did have a few years were I semi-seriously bicycled for exercise, but it came to an end in my late 30's.
At age 44 I then decided to start running. My BMI at that time was probably around 30, so I was borderline obese.
Over two months I run/walked 8 sessions of 2.5 km each. (Not kidding). Then I took a break for two months. Or perhaps I ran for those two months and just didn't log them for some reason. After the break, I started to run continuously in each session, and my best mile of the very first session was 9:52.
So for a mid age person bordering to obese, 10:00 seems very realistic off the couch after a few sessions.