When diagnosed they 4 lesions that were quite small. I have had sereal since showing "several" lesions. I dont know what "normal" is as far as new patients. You might have quite possibly had damage occuring "silently" before diagnoses. "silent" activity of the disease was theorized a few years back. Which means demylenating continues silently without showing any "flare up" symptoms. My last MRI proved it because it showed "Active" lesions while I was feeling great and was recovering quite nicely. I don't think you can use your MRI findings to predict how you may or may not progress. I know its scary and fear of the unknown is big for me too. What really helps me deal with that is faith. To the 100% certainty that I will get better. Not I hope to get better or I might get better or Maybe I'll get better. Thats what I strive for however. I fall short.
Good luck to you!