Have I made a wrong choice picking tank?

I finally wanted to try out an MMO. And choice was pretty obvious. I knew about warcraft and final fantasy being the top dog in this genre and final fantasy giving a demo has become my choice. I picked tank cuz well I generally like melee combat and all. At level 18, my feedback would be game is a bit slow but enjoyable. I would have loved if the dialogues were actually voice acted but I found the story pretty good actually.

The issue I am having is with the character. I know I am very low level but still I feel like picking tank makes me do absurdly low damage.

Now i went to play this game without following any guide or anything, but struggling with damage I kinda looked up in youtube and found final fantasy early game is a slog.

But my question is, Am I doing very low damage because tank does very low damage or its going to be the same with every character till I reach like mid to end game?