That's good that you know you made a mistake. Now you know better in the future.
As long as your female has a nice muscle tone and doesn't look thin, breeding at 1124g isn't that big of a deal. 1500+g is just a guideline to ensure that a female has enough reserves to last her throughout the breeding season and not get egg bound from large eggs.
Some females can't even get to 1500g because they're naturally small. As long as the weight to length ratio to them looks nice, big, and healthy, I wouldn't worry.
And it sounds like your girl is still eating, which is a good sign.

This is a good site to look at the Breeding timeline:
http://www.ballpython.ca/gallery/breeding.html

Quick Do it yourself cooler incubator:
http://ball-pythons.net/forums/showt...oler-incubator

Good luck.