I was 16 when I read the first Harry Potter.
My mother asked me to read the first three in a hurry because my little brother's school was trying to ban them, claiming them as occult. She knew that would piss me off enough to get them read in the two days I had until the school board meeting. I made my argument, comparing the people on the board to Hitler and various other baddies (In my defense, I was sixteen) and I won. The books weren't banned and I had found a new literary obsession.
My favorite charater is Remus Lupin, and has been since I read the Third book. I never liked Tonks, so his marriage to her disappointed me greatly. It's not that I didn't think Lupin needed love, but hey...just not with her!
I also adore Severus (obviously!) and Sirius.
Of course, Gred and Forge rocked my socks, too!