Our brains work differently as we get older. Not just in the obvious things, but also I think in the fundamental structure of neurological connections. I threw in a bit of German a few notes ago. I found it very easy at school and did the GCE after just two years. Perhaps it was the rules and the logical structure, after all maths and science were also very easy. Yet I struggled in French. I never knew why. If this post is wrong, then I still don't.
Yet now I can converse ok in French, and albeit more slowly, can also read and write Spanish without any problems. More practice is a partial reason - most German speakers that I have encountered over the years have been fluent in English, whereas a fair proportion of the French and Spanish have not been. And I spent far too long at school concentrating on my French teacher's cleavage instead of her lessons. But that does not explain it all. I simply find languages easier now.
We rarely get something for nothing in this life, so I can no longer do complicated equations in my head. This is apparently normal, revelations in maths or science are rarely made by older people. But that's a fair swap for me, I'm a more rounded individual now…
… not only in the beer belly :)