The mistake is this: you are too young. Itch is only allowed for minors 13 years of age and older. And if you publish, you have to have consent of your parents.
When you made an account you confirmed that you are old enough and that you understand what you are doing. Both is incorrect. The moderator linked you the terms of service. You are unable to understand those terms. Evident by your posting.
If you seek a game platform for younger people, maybe try https://scratch.mit.edu/