She's 18 years old. Her Father can't forbid anything. Same goes with the people talking about her Father dragging her back home after ep 6. If he does that it's kidnapping. As far as bankruptcy, she has a co-signer so there's no danger of bankruptcy. Finally, if she needs an out there's an Armed Force's recruiting office in every town, all she has to do is sign up and take the oath and all student loan's are forgiven. All that all of the above require's is that Maya grow up and act like an adult.
There's no indication that a GI bill exists in the BaDIK universe, so I don't think it's fair to blame Maya for not using it.
As for what her father can do to her, it really depends on the situation. Yes, at 18 Maya is technically an adult and can legally make her own choices, but if she has no resources, few friends, limited practical experience and a mountain of debt, that legal ability is moot. The game explicitly says that Maya's father tricked her into a position where he is able to compel her actions, but the explanation for why that is the case does not make logical sense.
You can chose to interpret that as Maya being too lazy and/or stupid to realize the danger is illusory, or you can interpret it as DPC being too lazy to ground his drama realistically and resorting to the financial equivalent of technobabble.
I choose to interpret it as the latter because, for all Maya's faults, she WAS actively pursuing the only opportunity
the story presented as able to solve her problem. It's pretty clear she hated the idea of pledging the HOTs and completing Quinn's list, but she did it anyway because she felt it was her only choice. She does not acquiesce to her father's demands (Maya was actually trying to contact Josy at the start of the semester), and she did not wait around expecting Derek or the MC to solve all her problems for her. Indeed, she only accepted the MC's offer to help (if he offered) a day and a half later, after her father's visit made it clear she couldn't afford to wait any longer.
Personally, I find those details easier to square with the financial-babble scenario. I'm sure some of that comes down to me finding Maya sympathetic in general, but I do think it makes logical sense, too.
That said, I do agree that Maya needs to be an active participant in whatever resolution we eventually get for this. It's fine for the MC to take the lead in finding the way out of the mess, but Maya needs to take the lead in making the eventual plan into reality (even if most of the mundane busywork is offscreen). It won't be enough for her to thank the MC for saving the day.