hello there, i'm glad you ask this question, i my self experience the amazing growths of these iguanas, i've raise 3 so far and all but one were raise from hatchling. the two hatchling reach your iguana size of 28 in one years and 2 months, how old is your iguana do you know? because these iguana no matter what will grow up to be 5-6 foot long, there's some cases in stunt growth of a iguana, but if you've fed it right with greens then it will grow, i've got a friend that work at the vet once told me that some iguanas will grow lots slower if those iguanas dont recived enough uvb lights, or enough heat check to see if you have those setup correctly, if feeding is right and heating and lighting is right then you've just got a slow growing iguana that all it will grow bigger at a slightly slower rates then others just like we human grow at a difference rates. i hope i'd help you out.