Is it normal to think fanart not art?

Looks like you have a "the only real form of art is Fine Arts" kind of mindsets, so 1500s, so retro!
Not everything has to be extremely complex to be considered creative.

When people like things, they enjoy to make content for themselves and other people who like those things, it's perfectly normal

Well I don’t write fanfiction anymore but I used it as a gateway to writing in my early teens. It got me so into writing that I studied grammar and story structure for days and days. It made me strive to be a better author so people would enjoy my stories. It’s fun to ask “what if” questions about already existing characters. You’ve probably already done it in your head. Writing it down makes it more real.

I've sold fan art before, so I'm not one to consider it useless. XD

Some of the best art I've ever seen was fan art.

Fan art is just art made of a topic that the artist is a fan of. I'd say while fanfic is literature, but it's just not so well-written all of the time.

Fan art IS art. Fan Fiction is not literature. Some of the people that make fan art are incredibly talented. I've never seen fan fiction that's well written