IMO a breedable female for me MUST be 3 years of age.
I just wont risk a higher chance of egg binding or other complications. Im not inpatient and I'd rather breed around my snakes well being and not just because I could do it a year early.

I just think age is more important than weight. This year I will be breeding a 3 year old 1200g female and I should have no problem. If I had a 2 year old 1500g+ I still wouldnt breed it.

Not to say people havnt had success breeding younger than 3, because I know they have but its just something I dont do.