>>Sketch+(OP)
If you're in your mid 30s now you'd be in your early 20s when Avatar the Last Airbender originally aired. Since it's a children's show (Nickelodeon), you wouldn't have been in the target demographic, so I don't think that's unusual.
I'm your age and I never even heard of Avatar the Last Airbender. I'm sure my younger cousins know about it.