The Short Version
The OECD has indeed formally called for special protection of children's personal data and recognized that misuse can cause serious, long-term harms—making the claim substantively accurate. However, the specific phrase "lifelong consequences" does not appear verbatim in OECD documents; the closest such language comes from the European Data Protection Board. The claim is a reasonable paraphrase of the OECD's position but slightly overstates the explicitness of the organization's wording.