Based on your hand as a reference, I would say he looks similar to my 11 week old picture in my thread. As I mentioned, if the previous owner didn't provide an adequate diet and proper UVB, they can appear to be quite younger than they actually may be. I could honestly say he could be anywhere from 4-9 months based on the fact that you have had him for 3 months, but I would be leaning more in the range of 6 months. He has obviously grown since you have gotten him based on the pictures in your first post. You live in Hawaii, so yours would greatly benefit in an outdoor cage. The climate there is very accomodating to Jacksons, so providing a good gutloaded feeder variety should insure that you'll have a good animal, granted they are not infected with parasites.