Hello mamajay,
I think you are absolutely right. You can continue breastfeeding as long as the milk is still flowing. Ladies who stop their children from breastfeeding do so for some selfish reasons. It is argued that they do so because they want the breast to remain firm. As you can see, this is a selfish reason which does not make any sense. What I know is that you can continue breastfeeding until the baby refuses to. When I was in school, in grade 4 I used to admire my cousin who used to go home and breastfeed. I think he was about 8 years old. The mother used to enjoy it since the boy was the last born. Also, studies don’t say that breastfeeding is a problem. In fact, there are no known side effects of breastfeeding until the milk stop coming. Mother’s milk is good whether the baby is big or not. However, most people breastfeed up to two years. At this point, the baby’s immune system has fully been developed and the kid can be independent. The digestive system is also well-developed meaning that the child is already eating other solid foods prepared in the home. It is also in order to exclusively breastfeed the child for six months and introduce other foods thereafter. If the kid still wants to breastfeed, you can continue. If it does not, you can stop and introduce other meals. So my dear, don’t listen to anyone and let your child enjoy its mothers' milk.
Breastfeeding for a long time is a good thing. It is good for your baby's development. The longer you can breastfeed the better

Realistically 12 months. Stretch goal is 18 months. I think it’s hard to tell when there’s so many factors that are outside of mom’s control. Baby might decide to self wean early. Teeth coming in. Pumping not working out at work. Also the strain it puts on your body.