Feeling like a savant and worries of delusion of grandeur

I feel like a savant based on my restricted interests, is this normal? I don't mean to sound like I have delusion of grandeur, but that is this core symptom of ASD that I experience.

I am sorry for being worried that I have delusion of grandeur, some people will think how insane I am if I tell them that I am ten times more intelligent than them.

That is why it is very hard to tell the difference between restricted interests and Narcissistic Personality Disorder.

I am sorry that I said that, but some symptoms of ASD looks very similar to NPD by observation.