If she is financially independent (and it sounds like she is if she has a job, is paying her own living expenses, etc.), she can declare this and after a certain amount of time, colleges will treat her as an independent student prior to age 24. I’m not sure what the time period is, though, so she would need to research it.
If she contacts one of the universities that accepted her, it may even be possible to defer her enrollment until she is considered independent. I’m not sure about that last suggestion, but if she calls to ask about being declared independent, she can discuss it at the same time.