hmmm. Which book is that? I thought that your girl was only two years old. If you have had her for two and a half years and acquired her as an adult or sub adult, you should be fine. I would personally never try and breed a female under three and a half years old, and more likely would wait until she is four. Also, length is not near as important as weight. Never hurts to wait and be sure. However there is plenty to be lost by going to early. Whatever you decide, good luck!