I started the series when I was 12 too but when KH2 came out. I didn't get the first one when it first came out because it just did look that interesting to me when I saw the trailers. So KH2 is my favorite.
I try my hardest to own every KH game that comes out in the US. I never had a PS3 until I heard about KH 1.5. lol. Now my next goal is to save up for a PS4 for KH3.