Youngest age a growclock could work?

[Pantheon]

My 17mo is a very early riser. Is this too young for a growclock or worth a shot? Thanks!

Hi, we started the gro clock at around 17months for my early riser ( see my username!) . She has good comprehension and associated the sun and stars aspect with going to sleep and getting up quickly but I don't think it's necessarily changed her early morning wake ups. We did have to use some controlled crying in combination with the clock and now at 19months she has started to wake up around 0600 (instead of 0400/0500) and is content to stay in her cot until the sun on the clock comes up at 0630. So I think the clock helped and will continue to help as she gets older and for us it was a good point to introduce clock and sleep training at the same time.