Did the terms change recently? It used to say 18, now it reads 13:
Minors under the age of 13 not permitted. If the laws of your country of residence so permit, minor children may utilize a Prezi account established by their parent or legal guardian, with such parent or guardian’s approval. If you permit your minor child or legal ward (“Child”) to use
Minors under the age of 13 not permitted. If the laws of your country of residence so permit, minor children may utilize a Prezi account established by their parent or legal guardian, with such parent or guardian’s approval. If you permit your minor child or legal ward (“Child”) to use