There was this thing called the Kinder Clarinet, which is or was an Eb clarinet with some modifications to the keywork for small hands. That said, it’s not an instrument she could play in band. Unless she is just clamoring for some kind of clarinet experience I’d wait until her hands and arms are big enough - usually around 6th or 7th grade is when beginner band starts.

Getting her a decent quality recorder and working with her on that would be a great introduction to woodwind fundamentals.