R.H.
The most common age for self-weaning is typically somewhere between two and three. I will have to come back with the research studies demonstrating that, one of my midwives gave them to me. Of the many mothers I know that practice self-weaning, the majority of have fallen somewhere in that time frame, most of them closer to the three end than the two end.
Mine technically have self-weaned, but between pregnancies and sudden moves and the like, I don't know that they would have weaned when they did had circumstances been different. My one son in particular who weaned shortly after his second birthday was nowhere NEAR ready to wean, but he hated the change in my milk once I was pregnant. He finally couldn't stand it any longer and gave up.