Is it normal to want sex with my mom

i used to share a bed with my mom. some years ago now as i am now 18. when i used to sleep in the same bed i used to wait till my mom fell asleep and finger her pussy, play with her tits, suck her nipples, kiss her and put her hand around my cock. i never had the courage to put myself inside her but i wish i had, now i just want sex with her. i have told her about how i want sex with but she refuses but i wont be able to get over it till i have sex with her. what should i do?