Is obeying one's parents given precedence over seeing an unveiled foreign woman, and what are the signs of puberty in Islam?

Signs of Puberty and Their Shariah Obligations:

Puberty for males is marked by three signs: nocturnal emission (wet dream), the growth of coarse pubic hair, or reaching the age of fifteen. For females, menstruation is added to these signs.

Once a boy reaches puberty, the rulings of Shariah become obligatory upon him. It becomes forbidden for him to shake hands with women, look at them, or be in seclusion with them, because he is now a mukallaf (accountable) just like other adult men. Therefore, one must refrain from going to the women's prayer area and from shaking hands with or looking at non-mahram women, including cousins, even if they object. There is no obedience to a created being in disobedience to the Creator. One can seek the help of a family member to explain the Shariah position.

Obeying parents if they command one to enter upon women or shake hands with them is not permissible, because obedience is only in what is right (ma'ruf). You can explain your puberty and that what is forbidden for men is now forbidden for you, gently and courteously, or seek the help of a relative.

A boy aged fourteen, if he has not yet reached puberty, is approaching puberty. He is not permitted to view the 'awrah (intimate parts) of women. Women should veil themselves from him, based on the Almighty's saying: "Or children who are not yet aware of the private aspects of women." If a child does not understand the affairs of women and their 'awrah, then there is no harm in him entering upon them. However, if he is approaching puberty and understands this, it is not permissible to allow him to enter upon women. Imam Ahmad was asked: "When should a woman cover her head from a boy?" He replied: "When he reaches ten years of age."

Reaching the age of fifteen according to the Hijri calendar is one of the signs of puberty. Your cousins must understand this Shariah ruling; it is not permissible for them to uncover themselves before you or shake hands with you after you reach puberty. You must not obey them in disobeying Allah. Your father must also realize this. There is no harm in explicitly stating the issue of puberty when necessary.