The quest gear is sufficient really esp at low level. Leveling content doesn't need you to gear up that well anyways.
As a tank at lower levels that's not necessarily true. You'l want to be constantly geared up to the highest level gear you have, since at low levels you'll have a hard time holding enmity(aggro) on enemies in your first few dungeon romps due to tanks not having their high enmity skills yet. At the very least, always update your weapon.
The first dungeon is Satasha, at minimum level 15(You'll probably be higher level because of the boosted EXP via MSQ(Main Story Quests)). I'd recommend heading to Aleport and stocking up on tank gear there before you go in. Also, make sure you've kept up with your Gladiator class quests; you'll get Shield Lob at level 15 which is very useful for grabbing stray enemies that have dropped aggro on you, and for opening against groups.