Your dad sounds like a good guy. You can either do what he says, or you could try to convince him you will not get caught by police. And if you smoke at home, you won't. As Marley has said:

"cos ini no expect to be justified
By the laws of men - by the laws of men.
Oh, true they have found me guilty,
But through - through jah proved my innocency."

Pretty much, just because it is illegal, does not make it wrong.

You know even Jesus broke the law, and many biblical scholars say that cannabis is mistranslated in the bible.

Explain to your dad that you will not get caught if you smoke it at home, and that you are not done experiencing this new thing in life. Maybe you could reason with him, if not, respect his wishes(or at least, don't get caught).