At what age did you put your baby in a toddler bed?

So my daughter is 18 months old. She has been sleeping in her crib but she keeps getting her legs stuck in between the slats of the crib, even with a mesh crib liner on which is supposed to prevent that. It will wake her up from a nap and she will start crying because it hurts. Is she too young to switch over to a toddler size bed? One that sits real low to the ground and has a safer railing to prevent falling out?