I was under the impression that, due to the changes in the brain's plasticity, if you didn't pick up maths before a certain age you probably wouldn't be able to

I was under the impression that, due to the changes in the brain's plasticity, if you didn't pick up maths before a certain age you probably wouldn't be able to pick it up with ease after that. If this is correct, and she was older than that age, then there's a good possibility that there's not just IQ involved here.