Idk What To Do With This Situation

I'm super frustrated with my kid right now. My 12 year old daughter has an assignment due Tuesday. I didn't know about it and she's had it half done for a MONTH! She left it over her friends house who is picking her up for school Monday. She asked me if I can finish it for her and bring it in before her science class at 10:30. I have to help my 16 year old son with his homeschool and take him to his urology appointment at 9:30 for his overactive bladder. I kept having to reschedule because I needed to have tests and stuff done on my daughter to see why her periods are hurting her so much. That I was fine with, but I can't reschedule his appointment because she was being irresponsible. Should I reschedule his appointment AGAIN or let her take her F. I'm just so annoyed rn.