OK Cutiepatootie...
You can wear letters NOW...

Just do it girl!
Look for a skirt and top in white...Try Penny's or the equivalent of Macy's - Eddie Bauer also. Catalogs such as Land's End and Chadwick's may have someting too...You can always make something like you said! I tried to look on the web and when I entered white dresses I got so many sites for Mormon special white underwear!!! LOL!
Congrats...
And having the badge is one of the highlights...I too didn't stop looking at it or wearing it when it came. It was similar to when I got my engagement ring...
Best wishes!
Maharet