Selective schools, though require a high standard to get in, cannot expect everyone to be clones - ie good at everything, it would be a boring place if that was the case.
I was at KEHS ahem decades ago, some girls were good at maths and others used to turn green at the thought ( I suppose it was relative - they were all good enough, just some rather better). I managed the maths and science fine - but Latin and French ....
yes well I managed enough to get by (and a C in O level Latin!) - but couldn't wait to dump them after Upper 5th.
When it comes to A levels - pupils do science or arts or languages etc (generally) - each to their own...!
I doubt of your DD, if she can do the VR and NVR will struggle with maths at school so much that it causes mega problems - maybe a little
but not too much....