You definitely need to get the job stones as all the people above have suggested. Other than that, don't be influenced by old players that might say paladin sucks or warrior op. All tanks are capable in tanking effectively and have 3 major similarities.
Mitigation,Heal or damage converted to hp and tank/dps stance. The only thing that is different is how you play them and how you use your skills to your advantage.
I main warrior since i have started playing and after 3 years i am neither bored nor i feel my class is underpowered in any case.
If you plan on doing savage (late-game) content where the difficulty skyrockets, i recommend that you stick to 1 tank class or if you prefer to level all of them then pick the one that you feel most comfortable to play with.
Good luck and welcome!!