Usually, when your child is between the ages of 18 months and 3 ½ years old, they can start transitioning out of their crib and into a full-sized bed. If your child expresses interest in a “big-kid” bed or starts climbing over the rails of their crib (this can become a safety concern), it’s time to look for a bigger bed.
There are some toddler-sized beds, though your child would only be able to use it for a few years at most, so you might prefer a twin or a full bed. A full bed can seem a bit large for your child right now, but in a few years, the extra space will likely be appreciated and you won’t have to worry about changing their bed multiple times.