I had similar issues as a teen. I think it was mostly caused by my sleeping too much - I used to sleep a lot as an escape. I would sleep late and just not have enough time to shower. Not having access to a comfortable, warm bathroom and a decent amount of privacy had a lot to do with it too. My mother was not the greatest at coaching me on hygiene issues either. She would discourage me from doing normal girl things like shaving, upper lip grooming etc.