Exersaucer age

When can my baby start using an exersaucer? I noticed my friend who’s baby is the same age as mine, 3 months, put her little one in an exersaucer for the first time. Is that too young? I can’t remember when I put my oldest son in one since it was so long ago. We don’t have one yet but I’d like to buy one, but since they take up so much space I’d like to get one when she can actually use it. She’s pretty tiny for her age but she can hold her head up perfectly well