Breeding ball pythons is not an exact science and is open to opinion and interpretation.

I personally don't want to pair my girls until they are 1500, though I do have a girl that is 1300 and 4 years old that I will breed starting nov. 1st. I feel that a female who is on her 3rd or 4th winter and on the light side is much more likely to lay than a 1500 girl on her 2nd winter.

Eggbound females are not always the lighter females and it is always a risk to be aware of when breeding any female.

Also be sure to have your incubator and space for the hatchlings ready before you start pairing so you aren't scrambling to get it together when your female lays or your babies start hatching

Also, the start date doesn't mean anything. You can breed them anytime during the year. Some people like to do a temp drop in the fall to simulate the seasons changing, but Ball pythons live very close to the equator where there is little temperature change between seasons. I started pairing one of my females back in May and I've seen multiple locks over the past 6 months. No eggs yet though!