No problem, don't worry about asking.
If you would please look, the comment that Pokemaster dated that the changes were open was in March, a good month or two ago. Username changes only last 3 days, and after that 3 days, no changes can be made. anyway, if the title says "closed", it is unable to be answered. If you can't answer something, just assume you're not supposed too.
Names can only be changed now if they interfere with the site (for whatever reason that might be). If you'd like to change username, I'm afraid you will have to wait for the next season change. That will be in approximately 2 months I believe.