I know this won't be popular with the child led weaning folks, but all my dc have done this at about the same age. They suddenly want to go back to newborn nursing schedule. So this is when we stop, cold turkey. It has never been difficult, extra cuddles and get really busy out and about for a day or two, always went really well for us.
Honestly, a nursing relationship has to work with both mom and baby. I'm usually ready to be done by 18m. I would never stop before a year, but I feel ok with 6months more.
~Rebekah~Mother of 9, 6 of whom I have the honor of raising, 3 with Jesus..