system
Given the following post, respond as if you're commenting on Reddit:
human
If I didn't know how old I was and there was no documentation, how could my age be determined and to what degree of accuracy?
gpt
Lets assume that there has been no strenueous aging done by extenuating circumstances like heavy drug use or osteoporosis and things of that nature. There are actually many ways to deteremine roughly how old somebody is. One of the most sure fire way is the skeleton (I am including teeth in this too as that is another good way). This is due to the human bones growth patterns. Children are easy to identify by size (obviously) and the fact that they will have closer to 210 bones as some bones fuse into one larger bone as we age. People who are of late teens to early 20's will have underdeveloped clavicles, as they do not finish developing until around 25-30 or so. Elderly people can be identified by loss of calcified bone cells, meaning their bones will be much softer and more brittle. The cranium actually yields some results as well. As one ages, the sutures (where the cranial bones fuse) fade and become less obvious. So this could  easily differentiate say a 20 year old from a 70 year old at first glance.

There is one way that can be seen microscopically. There are what are called 'osteons.' These are the individual functional unit of a bone, like a nephron to a kidney. As humans age, the osteons become smaller and larger in number, where younger humans have much larger individual osteons. Obviously these tests would have to be performed by a doctor in a suitable lab with suitable equipment.