The wording on this spell is a little confusing to me.
At Higher Levels. When you cast this spell using a spell slot of 3rd level or higher, the damage increases by 1d8 for every two slot levels above 2nd.
Does this mean the damage increases when cast as a 3rd level spell, then again at 5th, 7th, etc? Or does it start at 4th, then 6th, and so on?