What is the ruling regarding someone who curses the religion with the intention of cursing a person, whose age ranges between 12 and 13 years, and who does not know whether he has reached puberty or not, and what should he do?

Cursing the religion is an act of disbelief (kufr) and apostasy (riddah). The perpetrator must repent and show remorse, pronounce the Two Testimonies of Faith (Shahadatayn), and, according to some scholars, perform a ritual bath (ghusl) if they are an adult. If they are not an adult, there is a difference of opinion regarding the validity of their apostasy.