I'm not sure what to do?

[Lulu]

Hi everyone, so last summer my mom and step dad got a divorce and my step dad moved out. He had a daughter in my grade and she goes to the same school as I do. His new apartment is in the next town over and therefore they no longer live in the school district and that means his daughter has to change schools. My school recently found out about the move and they sent a letter saying that they had to leave as soon as possible. I haven't talked to either of them since the divorce so I do not know what is happening with the entire situation. I am very curious to know if she still goes to my school because I haven't seen her around lately. I guess my question is: should I ask someone at my school (I was thinking about asking her teacher) ? Or is it no longer my problem? We grew up together so she was like a real sister to me and I would be upset to know that I would never see her again. Thanks so much. Btw I am 14