He wants to marry me religiously need advice!!?

So hes Egyptian Muslim, and im Christian. He wants to marry me this week at a mosque but he told me he doesn't want my parents knowing yet nor his parents he said wen the time is right but I really like him and he likes me and he said when the time is right I should tell my parents then we can get married legally. But do u think its a good idea? He said he also wants to show his love physically but he cant will were married religiously