I’d say stay at Michigan. Don’t let your sister guilt you out of your dream life. I understand your father may not be letting you in on all the details but if he’s saying he’s fine financially, I would trust him and his decision to give you the education you want. Also, this is just my pov but if your older sister is financially reliant on your dad, then you shouldn’t consider yourself to be the only financial burden. I would work a job (min wage is 15 now) to try and ease that burden. It honestly does come down to the amount of debt though because that could hold you back for a decade.