I agree with evaunit. You said sewing wasn't your strong point, and I think the judges saw that. Not saying it's not a good costume, but in the context of a competition, I think it needs some work. Yeah, lights are cool, but those alone shouldn't get you an award.
Conventions for 2015 (so far...): Momocon, A-Kon, Otakuthon, Sac Anime
Cosplay line-up: Mayoi Hachikuji (Bakemonogatari), Nona (Death Parade), Nagisa Momoe (Madoka Magica), Menma (AnoHana), Tsukihi Araragi (Bakemonogatari)