14 is a bit young to rule alone so she likely has a regent handling her posessions. Or at least she had one until recently.She'd be feeling pretty much all the emotions at once, which she probably can't handle.
Hopefully, she has some loyal staff who will keep her form doing anything stupid. Left to her own devices, she could do anything.
The smart move is: be a baroness. She doesn't really have a claim beyond that (she's not a legitimate heir so no claim to the crown) and she can't reveal her secret without weakening the only one inclined to do anything for her. Baroness ain't a bad gig, she can possibly marry up or otherwise combine her holdings to get even richer and if she can one day come to understand why her mother kept the secret she did she can live as happy a life as nobility allows.
But 14 year-olds aren't known for doing the smart thing.