Is there any way I can change my username?

I'm sorry there isn't. You're not the only one who hates your यूज़रनाम though, at least Jeffersonian is simple to remember and can be shortened to Jeff which is kind of cute (wait no, *sobs* Jeff Goldblum ruined my प्रिय दिखाना so I hate the name Jeff), try to find some positive things about your name eventhough आप don't like it anymore. Oh and don't rant like me, you're supposed to find that oddly placed टिप्पणी दे funny (It's probably not though) so you'll forget about how much आप dislike your username.