No, you weren't wrong. You can make your own choices about your life. It's not fair for your sister to get mad that you don't want to do what she wants you to do.

I may be hyper sensitive to this, but my mother does stuff like this, giving me things that I don't want as a way to control me. If someone offers to give you something you don't want, or wants to do a favor you didn't ask for, they are not necessarily being nice. They may be trying to help, sure, but they may also be trying to control you or make you feel beholden to them.

If you would like to live with your sister, then you could probably figure out a solution to the traveling alone issue, but it's perfectly valid not to want to live with her. If you change your mind, I bet she will still help you get down there.