Help help help!

So, long story short, I allowed a teenager to live with me because of her mothers drug problems. I never got guardianship or legal custody because every time I asked about signing papers, her mother said she wasn’t going to be with me that long. I lived well outside driving range to her school and schools near me would not let me enroll her without being her legal custodian, so her mother, after months of fussing, sent papers to enroll her in homeschooling. She worked on this program the whole time she lived with me, but later found out it was not accredited and did not count toward her diploma. She lived with me for about 8 months when she was 15 and never returned to her regular school once she went home.

I just found out that her mother was arrested for her truancy, and not appearing in court. Even though it’s been years, the girl is 18 now, could I be held responsible too? Since she was under my roof, attending an unaccredited school?