Always remember that, for pve stuff, the XP is in the quest turn in.
Seriously though, it is so easy to outlevel your content. Just by doing your class quest, all the side quests you can find, then the bonus quest series, then the Heroic 2+ & 4+ quests, the occational Esseles/Black Talon run, occational Warzone, occational Space Mission. SO much content in this game.
I'm level 35, just finished Act 1 and I outlevel my class story line by about three levels.