New growth thin and yellow. First time indoor grower and opinions!

Did forget space heater one night. Got to like 62 degrees

Hmm, could be a early onset of a bit of nute burn.

Also is that powdery mildew? on the left side of the pic seems to be a few white spots.

Environmental factors might also play a part in this.

Too much light? That seems most obvious but it could be a transpiration issue showing as light toxicity.