DD1 moved into the toddler bed when DD2 arrived (she was almost 19 months) and she was fine. DD2 hated the rails in the cot and was getting increasingly harder to get her to sleep so we converted her cot to a toddler bed (with side rails) and she is great. She was about 15 months old. DD1 really wanted a pillow so we got her a really flat cot pillow and DD2 has only started using a pillow and she is 20 months old.