Make a donation support here, http://www.opblocks.com/forums/donation-support.49/
and state that you would like the rank upgrade applied. If you don't remember the exact date of when you purchased your rank try to guess and state that you don't remember.
@RawrWithFar, if you show staff you're able to handle a higher maturity with a low age, you might have a chance. The 13+ age rule doesn't affect anyone.