Well, first - wrong forum.
Second, not a good idea. Latex is bad for a number of reasons - the shininess, you mentioned for one. Under the proper conditions, latex and things of the like can be shot well... but if you're going to a con, the standard camera will take horrible shots. Second, allergies. People have latex allergies. You don't want to wear something like that surrounded by many people who may have reactions to it. Thirdly, latex does not breathe and you will have an absolutely miserable, hot, sweaty time.
There are plenty of fabrics out there with low luster, that offer the perfect amount of shiny in photographs and are much more comfortable and non-allergenic.
I'm not saying it can't be done. I'm sure there are plenty of well made latex costumes out there... but I still advise against it.
Fem!Matsuoka Rin (Free!) - 95%
Botan, Kimono ver. (YYH) - 15%
Kamiya Kaoru (Rurouni Kenshin) - 100%
Gakuko, Shanghai Disco ver. (Vocaloid) - 70%
For the Future:
True Form Midna - Legend of Zelda: Twilight Princess
Malon - Legend of Zelda
Snow Queen Elsa - Frozen