Liana, you're not going to like what I am going to suggest.
I'm sorry to say, but it doesn't sound like you did your homework in the amount of care a young puppy needs. You're away too long during the day at school, as are your parents at work, unless they work shifts. Any other family member at home? Is it possible you can return "Maggie" to the breeder for a full refund, and get another one when you're finished your school term? Summertime is an ideal time to potty-train her when you would be home a lot and you would be able to train her and give her the attention she deserves.