Is it wrong to drop dad's last name while under the same roof as him and my mom?

so im going to be moving out and to college in a few months. i hate my dad for the way he treats me, and doesn't appreciate me. (he is a terrible alcoholic) i have always disliked his last name (mine) for the way it sounds, but subconsciously i know it's cuz i hate him. i turn 18 in july and am planning on going to the courthouse and changing it to my mom's maiden name. she has a hyphenated name anyway. i am close to my mom's family, but dislike my dad's they are all cold. my mom knows my plans, and shockingly she said "you better do that when you are long gone." i said no next month, and she was like "that will really hurt you're dad, don't do it." yet she knows he is horrible and i hate him. Am i wrong? i dont think it matters if i change it cuz i plan on getting married in like 4-5 years anyways!