Is it permissible for young people to masturbate as an alternative to fornication, knowing that they pray and fast?

You have done well in avoiding adultery (zina), and you must also avoid the forbidden and greatly harmful masturbation. If you sincerely resolve to abandon it, Allah will assist you. Marriage and fasting are among the paths to chastity. Beware of befriending unrighteous girls, and instead befriend righteous people who invite to Paradise. For more details on masturbation to ward off adultery, please refer to Fatwa No. 102149.