This is more of a support question. Please post in the “Support” section of the forum; your question will be answered MUCH more quickly over there.
You should have a “User” page for your admin account. This can be found under “Users” in your admin page. Click on your admin name, and in the next window, look under the “Name” section.
See where it says “Display name publicly as”? This is the name that will be added to posts when they are created.
Please let me know if this doesn’t help you.