Age, you could be off by many years. What makes me think this now is that the problem being a calcium deficiancy, it happens over time, many importers get hundreds, and you may see a handful survive, yet they are still small, and sold as long as alive as hatchlings.
They keep them small, feed so little so they stay small, then sell them next year or the following as hatchlings. Ive seen a cape banded WT that was CBB, he was 6.5 years old when I got him for my friend, he was only 18 inches long. I spoke with the breeder who said the white marking on him stood out and he hadnt had any with a marking as such for a long time, easily 6 plus years.
Just reference it as obtaining it at that time, do not worry about actual age, so many get hung up on it and cannot get the real age. One of many reasons I like CBB monitors, they are so much better captives, also you know how old they really are, worth the high price you pay, and the trouble you go through to find a real CBB.