You don't really have to meet the guidelines, just PM a super mod and they'll change it for you (Palaeos, Jackie1st, or Zaralith).

(This is coming from my friend he's beside me lol but he said he just PM'd them and they changed it for him in a week and he didn't have to give a reason)

Here is what I pulled from the Planet Minecraft Official Guidelines page:

"It is possible to get your username changed on Planet Minecraft if you meet certain guidelines. The guidelines below will outline what is acceptable when requesting a change of your username and how you can make that request.

Valid Reasons for a Name Change:

• You misspelled your username
• Your username contains personal information such as your real name, age, location, etc.
• You did not correctly capitalize your username
• You have extra characters in your name that you need removed
• Your Planet Minecraft username is different from your Minecraft username"