I was in my first heroic about 15 minutes after my group turned 80(I had to train skills). A lot of dying followed but I did clear a few heroics with level 70 overpowered badge gear and quest blues.

The hardest part about starting heroics is jumping over the gap of "the tank died before I could cast a heal". I recommend picking up "daunting" plate set and titansteel tanking pieces if you don't have something better. There's also gear in those forgotten about normal level 80 instances.