Did you bother to check her timeline lately? When she could train?
Do you have an idea of what makes a good neurosurgeon, and how old they are when they start operating? Did you know real people at 18, who later became neurosurgeons? She has brains (with a capacity for quick well-thought decisions), she's exceptionally well-wired, she's hardworking, and good-willed. For me these are the main criteria. Oh, and by the way, if you were interested in her, you might know that at the moment she's no more planning to become a neurosurgeon. I wish her to be happy above all, I trust her to make her choices better than me of course, maybe she's not wholly decided yet, she still has three years to decide, yet my opinion is still that she has all what makes an excellent neurosurgeon — which doesn't mean that I believe she should, of course. Just, it's an option well at her reach.