If you can find a way out of that, for example by avoiding knowledge of identity, the service could be safe to use. Maybe you could take payment in a privacy-protecting cryptocurrency (not Bitcoin) and have the users connect with a tor browser.
Even if there is a problem, how is it not better to address that? If the parents don't feel safe, they will avoid all those service providers. The kids don't get help if using the service providers is too risky for the parents.
In any case, there will be no talking if the parent would need to trust you but doesn't. That doesn't help kids.
You can't change the law, but you can avoid having identity information to report. Parts of the solution probably involve non-attributable cryptocurrency and tor browsers.