What is the ruling regarding the prayers I performed during adolescence after masturbating, without performing ghusl, and do I have to repeat them?

Praise be to Allah, who guided and enabled you to abandon that reprehensible act. As for the ruling on the prayers you performed while doubting the emission of semen, you are not required to make them up, because doubt about the emission of semen does not necessitate a ruling. However, if you prayed without performing ghusl (definition), while being certain of the emission of semen which necessitates ghusl, then according to the majority of scholars, you are required to make up those prayers. Some scholars, however, hold that you are not obliged to make them up due to your ignorance of the obligation of ghusl.