White could be good. Really good. It could stay white (which would not be bad) or change to super yellow. When picking a hatchling out, I look for ones that are more white and super clean rather than cream or brown with a more "dirty" appearance as sometimes these turn out to be the real screamers down the road. I am sure some of the cream or brown ones change to clean and brite yellow as well though. The onto genetic color change is probably my favorite part about Carpet Pythons.
I am by no means an expert and hopefully someone with more experience will chime in, but I do not think there is a definate time period for the change to come on or complete. I would think that some of it has to do with the size as well as the age but in general a good deal of change would be seen in the first year and more over the next year.
I would really like to see pics. Any chance you could post some? I will understand if it is not an option.
My advise would be to feed him like crazy, if he feeds well. It seems near impossible to over feed a young, healthy, and growing Python. I would be more careful with over feeding as maturity sets in but for now feed him and feed him (more food = more snake). This will cause the shed cycles to speed up and hopefully the color change to pick up as well.
What are you feeding him? Some Jungles tend to get stuck on mice which is no big deal when they are young and small but a real pain once they get bigger. Try a rat, unless you have already. JMHOs.
Hope all this helps and again, hopefully others will voice there opinions and experiences.
Later.
Kevin
....LOL