It's sorta funny that my 'first' memory wasn't actually from the first time I attended NDK. I had to remind myself that was the second year, so I'll tell both! Story Time!
The first year I didn't really 'get' cosplay, but I had friends that did it and I wanted to play too. So I picked a random DVD cover and said I'd make that outfit, which turned out to be Lacus Clyne from Gundam Seed. Well, my friend had made a Zechs Merquis costume had forgotten her mask in our room. Since she and my other friend were in line to sign up for the costume contest, and her boy was MIA, I said I'd get it. So after getting up the elevator, getting the mask and getting back down I knew I was running late, so I literally ran to find them. Please note that I don't run on principle, and never ever in NDK any more. Well, the shoes I had on for Lacus had once been dance shoes and still had the metal on the soles, and when I hit the 'cobblestone' I slid like a maniac. I luckily have pretty good 'panic' balance and didn't fall, but as I skidded past, with Zechs' mask held high, I heard "Wait, was that Lacus sliding past us? What was she holding??". I tried not to die laughing.
The first memory that popped into my head though was from my second year. I was debuting my first Official Cosplay version of Catherine Sforza from Trinity Blood and had thus far run into a lot of 'Oh you're from that one show!' and was starting to get a bit bummed that no one knew who I was. Walking near the bar I felt a tug on my skirt I looked down at the most adorable little girl dressed as Kikki from Kikki's Delivery Service. In a very quiet voice she asked if she could have a picture with me and I just melted on the spot. I'm very sad I never got to see that picture, because it made all the other comments of the day just seem silly to worry about.