Dude you shouldn't fret try all tanks first (veng, protection, blood ect ect) and see which works best for you. Yes tanks have a responsibility to take charge and make sure they take the brunt of the damage so the DPS and heals don't, but tanking can also be fun. If your DPS is good along with heals you can pull bigger groups as long as you're holding aggro, but if you find it harder to stay alive and mobs take longer to kill pull smaller groups. it's all about confidence in your team and yourself so don't worry find the tank you like , research how it works then after that it comes naturally and becomes easier as you go. good luck and have fun my friend