I don't know if you realize it, but you are very lucky to have doctors that are taking you seriously and working to diagnose you. One thing I would like to mention, you did not say what kind of MRI results you are waiting for, but it is important to scan both the brain and the spine. I was investigated fairly early on for MS, but when my brain MRI was clean I was dismissed. Two years later I had a spinal MRI, which showed lesions and led to my diagnosis.
As far as your age goes, MS has never been shown to fit nicely into a box, so I wouldn't expect it to start now. A lot of your symptoms could be related to MS, but they could also be caused by something else, so be patient, and I hope you get it figured out soon.
Be joyful in hope, patient in affliction, faithful in prayer (Romans 12:12).