[@Crimmy]Quentin is a One Year War veteran whom had been picked out to pilot a standard GM unit. He wasn't the caliber of Char or Amuro by the end of it but he had established himself as a highly reliable pilot by the end of the war even though he officially retired from piloting shortly after it ended. After the Delaz fleet incident he re-joined the military as a member of the titans. He served with them for a time before defecting and playing a rather sizable role as a field commander for Karaba. After the war he kept serving with the AEUG until the formation of Londo Bell. He then proceeded to serve a minor role as a combatant in the events of CCA though he wasn't present for the final battle. It's due to his long career of established military experience and talent that he was chosen to be given the suit. Unofficially it is an attempt to see if they can turn him into an icon like Amuro, or Bright. 

If for one reason or another this is unsatisfactory an answer then I'll simply change the suit if others have a problem with it. I chose the suit out of character because I thought it'd be a strong ace suit for the team.