A. Can watching porn,trying to masturbate,bad friends,sexual talks and thoughts all the time, cause puberty to cause somewhat earlier.
There are studies (from the west) which imply that the teen mind (boy or girl) which is exposed to various images, actions, acts and behavior affects the developing brain. The immature(sexual) brain is suddenly exposed to too much of visual and auditory information that these youth try to imitate, carry out and perform sex and try high risk sexual behavior too.
As they mature, the body full of hormones and these information prompts them to indugle in physical sexual contact. As time goes by, such individuals has a tendency to see intercourse and sexual behaviour as purely for sexual gratification instead of intimacy. When they get addicted to porn, there actual satisfaction with a partner or spouse is not very rewarding.
Now, researchers are finding that the average age of puberty for boys and girls have come down significantly due to various factors and one of them, is thought to be is over exposure to unhealthy sexual knowledge. The fact that watching too much porn induces precocious puberty is Yet to be proven conclusively.
Precocious puberty is basically related to over-exposure of hormones either internally (disease of the hormone producing, hormone regulation parts of the body) or externally (diet and skin contact with creams and ointment).
Children who are at risk of developig precocious puberty include obesity,female gender, exposure to sex harmones,radiation therapy, adrenal hyperplasia etc.
B. If yes,than,will this affect the final adult height of the person in the same way as the precocious puberty does?
This question cannot be answered clearly because, as of now we do not have conclusive evidence that watching porn/ thinking about sex causes early puberty. True precocious puberty is associated with early growth spurt and then a quick bone maturity that results in a final shorter height.
The content of the questions hints indirectly that there could be an issue with addiction and a sense of guilt because of bad friends. It is important to understand that sexual practices with multiple people or high riks behavior can lead to unwanted health issues. If there is a doubt of addiction and someone needs help, they can approach to psychologists who are professional trained and experts in helping the person from getting out of the addiction.