I want to have sex with my little sister

I recently had sex fantasies about my little sister (about 4 months) and I want to have sex with her. We are both virgins and never had sex or tried it before. I’ve seen her naked and masturbating before and when I see her naked we usually just brush it off like it’s nothing due to the amount of times it has happened. I want anyone to give me good advice on how to act it out and actually make her have sex with me.