its a GREAT SIZE!!! the width will give a bit of overhang- the length is fine- you may have to tuck it in on the bottom- but he will love it just the way it is!!!
is he a little guy?or an adult?
if a little guy- he will grow into it-
if already grown---my sons tell me you can not make a quilt too long- they like them long enough to tuck under their feet when snuggling---
nothing wrong with long-
and as for what you did wrong?????????what size does the pattern say it's supposed to be? it seems quite (right) from the pictures- beautiful quilt!