Facebook would use the time to listen to "parents, experts, policymakers and regulators", Instagram head Adam Mosseri wrote.
It follows leaked internal research the Wall Street Journal (WSJ) said showed Instagram was "toxic for teen girls".
But in a recent blog, Facebook head of research Pratiti Raychoudhury called this allegation "simply not accurate".
Instagram requires users to be at least 13 before they create an account - but many children under that age use the platform anyway.
