OMG, I had one too! I loved it like a brother – it was the NJ Devils – and whenever I wore it (during my long-ago teens), friends would laugh at me because it was so big and mannish.
To make one more flattering…hmm. You could always do what those girls in Philly get done – have their mens’ football/hockey jerseys altered into dresses/cute skirt-and-top combos that are more girly. (I used to work at one such store…there was even a customer who bought a gigantic Sixers’ jerseys and wanted it made into a full-length dress for her PROM. /* o *\

I’ll post a couple sketches of styles typical to what we used to make as soon as I get back and have the use of a scanner.
Edit 4/17: I’ve finally posted those sketches here.

However, it’s been my experience that with a sports jersey, you’re severely limited by the polyester mesh fabric, the color combo, and the gigantic logo, and so you have to end up altering it into something that is still sporty instead of being able to hide its origins altogether. (And unfortunately the re-designs of mens’ jerseys like they do in Philly still scream 2003.) Perhaps you could chop it into something sporty and cute a la Alexander Wang? A cropped short-sleeve jersey (rolled sleeves) to wear with cuffed khakis and wedge-heeled sneakers?
What do you think?

xoox
Carly