If that's true, genuinely true, then she really, really will not enjoy A Levels. They are harder and much more time consuming. If the grades she gets for GCSE aren't great, and she had to absolutely slog for them, please do not steer her towards A Levels. It will be soul destroying. Don't keep impressing on her that the rest of the family went to university. It's not fair. She is not "the rest of the family", she is her.
Not everyone is "academic", and that's fine. This world would not function if we only had academics. In fact, we're probably among the most useless people, really. I went all the way in education, and I would have been so much better off learning something useful straight from school. I have lots of certificates and impressive qualifications.. but past a few impressive looks when you tell people, they don't get you as far as you might hope. When I tell people I'm a Dr, they're momentarily impressed, then when they realise it's not in medicine, they're not so impressed haha.
It would be much better for her to go into a trade, and get an apprenticeship. Is she interesting in hairdressing, beauty, electrics, brick laying, plumbing, dog grooming, baking, cooking...? There are so many very important careers that help the world keep turning, that don't require A Levels and university.