Pillow for toddler

When did y'all give your child a pillow? My son is 18 months, right now hes still in his crib but in two months he wont be since are moving and just going to put up his toddler bed then. But I feel like I should go ahead and give him a pillow to sleep on. He is always bunching up his blanket and laying his head on it. So I just personally feel it's time.