Impatience and ball python breeding do not go hand in hand. Patience is the key!
If you wanted to breed fast, just pick up breeder size girls.

Anyway, back to your question. Yes. It is doable to grow out those girls in time if they are consistent feeders. If you mean by next fall being 2013, then that's plenty of time. Not sure about this coming fall.
I have a late 2011 Mojave born in December that is 800g now. She grows at least 100+g a month. She's a beast.

But remember that just because they reach breeding size does not mean they are sexually mature. It takes at least 2+ years for a female to reach sexual maturity. If these girls were born this year, it would be safer to breed them after their second winter.