We all start somewhere. Don't sweat it.
To Deborah's points.
1) How much does Edwin weigh and what size are the weanling rats you are feeding him?
There is a feeding chart somewhere on the forum you can use as a guide. I think it is stickied.
If you don't have one yet, get a digital scale that measures in grams. You can find them on Amazon as either kitchen or postal scales. I even picked mine up locally at Staples.
Weigh Edwin after he poops and follow the chart.
If you are getting your frozen thawed from a local store, the weights can vary wildly. For that reason I grabbed a 2nd smaller scale that stays in my car.
For example at Petco, which gets their F/T from Gourmet Rodent, the ones marked as "Small rats" weighed anywhere from 39g - 94g (yes, I weighed every one they had, that night and I didn't care that the kid working that department stood there watching me in shock/disbelief)
If you order in bulk from some place like Perfect Prey, I've found the weights to be a bit more consistent.
2) If the prey was appropriately sized, then he may have just gotten disturbed and decided to abort.
Try to make sure you are feeding him at night. Dim lighting and quiet surroundings help.
Make sure the prey item is properly defrosted. I think normal body temperature for a live rat/mouse is around 96-102. Give the head of the rat a quick hit with a hair dryer and then offer.
Always slow and smooth but deliberate movements around him.
Once he takes the food leave him alone and do not disturb him. They are in a vulnerable position while feeding and any little thing can startle them and cause them to abort.