Babies can be breastfed for as long as 2 years as it is good for the neurological development of the baby, provided it is convenient for the mother and child. But if the baby can't be breastfed for this long, the baby must have been breastfed exclusively for 6 months initially,which i suppose you did. Halting breastfeeding at 1 year 2 months won't make the child lose any developmental milestones achieved already i.e if he is walking already, it won't stop him from learning how to walk, run etc