AITA for telling my step sister she can't stay with me?

I (f25) have a younger step sister Violet (f20) through my dad. We get along but we're not really that close.

Violet attends a fancy, expensive college close to where me and my boyfriend live, but a couple of hours from my dad and step mom's place. She's currently staying in student accommodation but her term finishes soon and she's taking a semester off.

Violet's dad had a college fund for her, but she's struggling to keep up with all the costs. She asked if she could live with us for the second half of the year while she sorts everything out. She won't be paying rent (but said she'd cover the increase in utilities and her own groceries)

I said no and suggested she might be able to transfer to a different college that offers scholarships, or one closer to dad and step mom. Violet said she didn't want to do that. I told her I understand where she's coming from, but she can't expect people to hand things to her. She should be looking for other options too.

Violet was pretty upset, and I texted her later that I get she's upset, but she can't make her problems everyone else's. She left it on read.

My step mom is also telling me to let Violet stay.

AITA?