Eighty grams is a fairly substantial weight for a female. So size will not be an issue. Females being "ready to breed" is more a function of size, not age, as in optimal conditions, such as out of doors in Florida in the summer, female panthers can grow to breeding size in as little as 5 months. Raised indoors, that is more of an 8 month effort. The key concern is whether she is properly prepared to breed, as many captive husbandry regimens do not prepare the female as well as is done in the wild. The typical deficiencies are with calcium and certain vitamins, resulting in females unable to successfully endure gestation, and/or the laying of good eggs, and/or the female then properly recovering post-laying. Unfortunately, your female is not programmed to know that it is deficient, as in the wild, deficiency does not occur to any measurable extent.
If your husbandry is weak in preparing females, then added time may benefit you, as females can store the vital resources needed so long as they are receiving enough to meet their own sustenance needs, and then some. But I want to reinforce that it is not so much a function of time, as it is one of husbandry. In the wild, these girls are impregnated as soon as they are willing, typically at about 6 months.