How many children do you have? I have 10, and they self-weaned around the age of one year with two exceptions. One daughter self-weaned at 6 months. She is the most stubborn, independent child to this day. And our youngest self-weaned at 15 months. But what do I know???
When I write average that average is based on broad cultural studies not just on this country and other Western nations. There is nothing unusual or wrong or anything that implies criticism in the fact your children self weaned earlier. It is not a sign of bad mothering or poor attachment bonds or anything else of that nature it only means one thing. Your children were ready to wean and as a good mom you understood this and went with this for the child’s benefit.
All children are different and have their own personalities from the very start. Average is just a benchmark. It is people insisting that it is wrong for a child to breastfeed at all after infancy that I object. Your situation was right for your children and no one else has any cause to write otherwise.