Your temperatures sound fine to me. When you get a crested gecko that does enjoy eating insects they do seem to grow a lot faster than others in general. Since I bought my tailess male in July, he went from 12 grams to 20 in only a few months. I only feed him dusted insects once or twice a week and always have fresh CGD. Somehow he just grows like a weed. If your gecko is smaller than one you saw at a show I wouldn't stress out about it.

Make sure the heated rack keeps the temperatures low enough for your little one. Prolonged heat has been known to cause a lot of problems.