Depending on her breed type and size, your puppy will start adolescence and reach sexual maturity at different times:

Small breeds:

approx. 9–12 months (adolescence from 5 months)

Medium breeds:

approx. 12 months (adolescence from 6 months)

Large breeds:

approx. 12–15 months (below 40 kg) (adolescence from 9 months)

Giant breeds:

up to approx. 24 months (above 40 kg) (adolescence from 12 months)

Although she may start to look like an adult, she is still very much a puppy and she will continue to be for some time, particularly if she is a giant breed, as she won’t reach maturity for at least another year. As an adolescent, she will be energetic and high spirited, and you must provide her with the opportunity to utilize this enthusiasm for life by channeling her energy through training, play and regular exercise.