My child prefers play and toys that seem younger than their age. Is that a problem?

Preferring play that looks younger than their age is often because it matches the child's developmental stage and they can enjoy it with a sense of security—so it isn't a problem in itself. Play is a source of learning and security. There's no need to force "age-appropriate." If you want to broaden experience, it's natural to use a favorite play as a doorway and add just a little that's new, or do the same play with materials that look age-appropriate. Make "is the child enjoying it?" your main guide.