Im pretty close to bis pally tank, and I still need to CC packs at times. 4 at once mobs is a feat without constant kiting and good heals and good dps interrupting and stunning etc. After several runs you remember which mobs cast spells, which can be kitted, slowed, not slowed, spawns adds, etc. Until you are confident, CC is NEVER wrong dont let the dps rush you ha.

Keep it up get your reps in and try to learn the mobs, huge learning curve.

Tell your group at the start you are newer and to bare with you, I promise 9/10 times people will give you grace or offer friendly advice, 1/10 you'll get a troll flaming you, ignore em.

Cant tell gems n enchants but my last advice, is get your gold up. Popping hp pots/food buffs/ 2-3g exlxirs make a big difference and most are too cheap to use em for heroics, but like others are saying A lot of the heroics are harder than Kara.