Like girl I don't know?

[Bob]

I went to school with her older sister and really like her younger sister. I don't know them and her younger sister goes to a different high school in my town. She is going to the local town college next year and I am going to a different one here but will be working in the cafeteria at the one she is at. How should I approach this situation?? I don't know her at all but see her all over social media.