These machines are not strong enough for catching most (and sometimes all) of
MS lesions. My first
MRI was considered bogus by my neurologist. No
lesions showed up. The next MRI showed lesions-- even a large lesion missed on the open one.
To answer your question, MS is a clinical diagnosis. If you have symptoms and lesions that meet the McDonald's criteria, and possibly other supporting findings (mimics ruled out), other diagnostic findings, then your age shouldn't be a factor.