AITA for not letting my little sister come to my college move in day?

So I (18F) have a little sister (8F) who originally was going to come to my college move in day along with my mom and stepdad. After realizing I could bring only two people and thinking about other factors some more, I decided that I wanted to spend that day interacting with other students without her there expecting my or others' attention. I told my sister that although I really really loved her, I kind of want to have this move-in day to myself, but we can have other chances to hangout. She seemed a little sad butunderstood. However, my mom and stepdad are really mad at me for this and say I'm selfish, and that this would mean a lot to my little sister.

So AITA?