Sexual maturity has more to do with size than age. In the wild, a female tortoise will not lay eggs until around 15 years of age. However, in captivity, tortoises tend to grow faster and mature earlier.Females can lay eggs at around 14cm straight carapace length (SCL); however, breeding very young or very small tortoises is not to be encouraged as the female may experience difficulty in laying the eggs.owever, in captivity, tortoises tend to grow faster and mature earlier. Females can lay eggs at around 14cm straight carapace length (SCL); however, breeding very young or very small tortoises is not to be encouraged as the female may experience difficulty in laying the eggs.