According to Dr Enlli Thomas, there is evidence that being bilingual "may provide protection against age-related memory loss".
(Language processing is one of the most complex activities that our brains carry out and the ability to be able to speak, listen, and think in two languages and of using two languages on a daily basis may help protect against the decline in the brain's abilities when ageing. I can only hope they're right, and that I didn't start learning German too late.)