I have been thinking about this for some time and would love everyone's feedback. All the pictures of Jesus I have seen painted always portray him as a 33 year old, and I believe this is incorrect.
Science tells me that it takes 7 years for every cell in the body to be replaced. In the first 3 cycles of 7 years we see the transformation of a infant to child; child to teen, and teen to adult. After 21 the growth process ends and the 7 year cycles are to replace the cells.
I realized when I first understood this that this is the reason we age. Because of sin in us our bodies do not replicate the cells exactly right and are a little off. Similar to a copy machine making copies of copies you get a deterioration in picture quality that eventually no longer looks like the first picture. Likewise with us; with each passing cycle of 7 years we age and look older until the cycle is so far off we die of natural causes.
Even with children growing to adulthood the effect of sin on their bodies is evident with blemishes, pimples, moles, etc. They just are not as noticeable due to the extreme changes occurring with their maturation.
But not so with Jesus. He was sinless from birth. Therefore he never had pimples or any other blemish, nor any sickness. When he reached twenty one, the next 7 year cycle would have perfectly replaced their cells, so at 28 he still looked 21. Likewise when he died at 33, five years into his next 7 year cycle, he would have still looked 21.
If God still uses this system when we get our glorified bodies, then we will all look 21 for ever.
BTW, as a side note, if men can say they are women trapped in a man's body, I think I am a 21 year old trapped in a 63 year old body, and I should get special rights ;).