OOP: James, headboy without having been prefect?

[jklb66]

No: HPFGUIDX 65678

James was not a prefect but was Head Boy--it actually makes sense.  
Now that (thanks to Snape's memory in the Pensieve) we've actually 
seen what James was like at 15, we know that he was NOT prefect 
material.  I certainly wouldn't have chosen James or Sirius for that 
role.  
However, something significant happens when James is about 16--he 
saves Severus's life when Sirius tells him how to get him in the 
Whomping Willow.  I can imagine that event making James stop and 
reflect on how he and Sirius have acted toward Severus up until that 
point.  A great deal of maturing may have taken place in young 
James.  It may have been that event, more than any other, that 
changed James from an arrogant bully into someone worthy of both 
being Head Boy and winning the heart of Lily Evans.
--Jennifer