I would say tell them but if they have a negative reaction to it, ignore it really. If you love singing then do what you love. It’s your life and hobby and your parents can’t control what you love and don’t love.
I’m a Christian too and I loveeee to sing all sorts of songs! My parents have been supportive of that! Just don’t sing songs that are like super inapropriate with bad meanings and bad words…… if you do like a song that is bad…. try kids bop XD