DH is a recently retired journalist; I dabbled a bit when younger but now work for corporate comms.
My advice in terms of first degree is find something that she is interested in and has a passion for. She can always go on to a post graduate course in journalism if she feels she needs to later on.
Any degree will involve researching, presenting and writing in some form and specialist knowledge can bring benefits and insights when putting together pieces.
In particular a degree in a scientific subject such as chemistry or engineering will give her specialist knowledge and confidence when writing/presenting on these topics (and people in the media tend to be humanities/ social science graduates so there is a strong demand for science knowledge).
Whilst at university get involved in the student newspaper/ website/ radio station/ tv station if they have them.
And in vacations or whilst a student get work experience so that she can put together a porfolio that contains more than just student stuff.
Contact local media and see if she can feed in stories by attending local events and reporting back or going around local area finding interesting stories - pay wont be great (if at all) but it will bring benefits in terms of portfolio of pieces of journalism.
Also try and get work shadowing / internships in media companies (sadly again not likely to be paid but worth it for the experience) Be prepared for lots of hard work. (Being in big city for university is useful for this as there will be more opportunities on her doorstep, but almot all sizeable towns and cities have a local newspaper/ media outlet of some kind).
Volunteer roles with charities etc can be beneficial - writing pieces for charity websites/ magazines/ leaflets can give useful experience.
And keep as broad a view of the media as possible - dont think just of the glamorous BBC presenter, Vogue writer or broadsheet reporter roles. Think of the specialist correspondents on the general publications and also specialist 'trade' magazines, things like British Medical Journal, accountancy, motor trade, law, food, housing publications etc etc - most areas of work have a journal/ news website of some kind requiring regular reporting. If successful use these roles to build up experiece which can be used to go on to the more consumer focussed roles (although these specialist roles are satisfying in their own right but keeping a few thousand chartered accountants informed every week isnt quite as sexy as appearing on the news at 10!)