I created and lost my Apple ID in one hour because of Apple's fault. Apple support was not able to help.

Trying to set up a new iPad for my 12 yo son, I made a "mistake" of entering his real date of birth. Then iPad suggested I set up Family Sharing on my own Apple device. I don't have another Apple device so I tried to change the date of birth. But apparently you cannot change date of birth once you entered it. I found information that this could be done by resetting iPad which I did. Now the problem was that the email I used to create Apple ID is already associated with an Apple ID. I tried to login to this Apple ID but I don't know the password (because I didn't have a chance of creating it). But I can reset the password! After I successfully reset the password I was presented with security questions in a non familiar language which Google translate said was Danish. I cannot answer the security questions because I didn't have a chance of setting them up. But I can reset security question! To rest security questions you need to answer them!!! I called Apple support. They said that what I did was impossible. They said these security questions mean that the account was created long ago because security questions are no longer used for creating new accounts. They said they cannot help and suggested setting up a new email address. As I write this message I am logged in to discussions.apple.com under this Apple ID but otherwise I cannot do anything else as I am presented with the security questions in Danish. Why do I have to create a new email address? How do I get my Apple ID back? I didn't forget anything. This was Apple's fault! This is a newly created blank Apple ID. How come they cannot reset it?