I’d say your neurologist doesn’t know much about MS. I read there’s a higher number of younger people getting MS than older, yet older people do get it. I could be wrong. Either way age is definitely not a factor or reason to suggest you don’t have it. Only testing would reveal that.

Are you seeing someone who specialises in MS? Who told you you specifically have primary progressive MS? They often want an MRI and lumbar puncture to confirm any type of MS, but it’s my understanding that not everyone has the lumbar puncture