Let's put it this way the bigger the better, breeding is not a race, you need to be patient.
Would I consider breeding a 1000 grams female? Yes however that female would need to feel right and be at least 4 years of age, which would generally indicate that the female will not be a big female and may have been a slow grower as well due to feeding issues, in that case breeding will generally jump start their appetite.
Usually I breed females at 18 months minimum and at a minimum of 1500 grams but again I prefer to breed them as big as possible.
Also keep in mind that because a female meet minimum weight criteria it does not mean I will pair her, I have had females that were over 2000 grams that did not make the cut because they did not feel right.
Obviously you have limited experience than which would lead me to believe that you should wait.In my experience the females don't even lay their first year anyway