I was super slow at first, too. But, I added intervals (and they can be short, like from here to the light post or something) of not even sprinting, but faster pace. Then I return to my slow pace. After a while of doing this, the slow pace speed gets faster, and now my fast intervals are as fast as I can go. Good luck, and no shame in running slow.
count me in as one that was passed by a racewalker while I was doing my snail's pace jogging...plus she was at least 10 years older than me, I'm 52! 
