¿Por qué siento dolor corporal, falta de período y picazón?

Puberty can start at different ages for different people and there is a wide range of what is considered normal. 
The ability to have children (reproductive maturity) usually occurs after the completion of puberty when the reproductive organs, such as the ovaries and testes, have fully developed. For most individuals, this occurs in their late teens or early twenties. However, it's important to remember that everyone's development timeline is different.

The chances of pregnancy from the described activity are generally low.. but not impossible. If you both are concerned it's best to take a pregnancy test after her next expected period. 

You may be experiencing a vaginal infection, which can cause discomfort. Symptoms of a vaginal infection can include an unusual odor, itching, pain, or abnormal discharge. These infections are often caused by fungi or bacteria. To address this issue effectively, consult a pharmacist. They can recommend specific pills or creams to treat your condition, leading to noticeable results. 

You have a small cut on your vagina after you were intimate. This is no surprise because the skin down there is delicate. It might cause pain, redness, or a bit of bleeding. To speed up the healing process, you can keep the area clean and dry, avoid using scented products, and apply a gentle cream or ointment recommended for cuts. 

Ovulation can cause small cramps or changes in vaginal discharge­. To confirm ovulation, women can track their basal body tempe­rature or use an ovulation test kit. The­se simple methods he­lp predict the most fertile­ days.