May. Not even a contest.
Let's get the obvious stuff out of the way first. I don't buy that "ten years old thing" for a damn second. She's got to be fourteen, at minimum, and even that's pushing it. I'm a senior in college and most of the girls I encounter on a daily basis have bodies that pale in comparison to May. Sugimori could have very well designed her to be older than ten, but the anime writers assumed, "hey, she's starting her journey. She must be ten!" and ran with it. Pic related, it's the original concept art for May. Those hips, that waist, and those breasts are not ten years old. There's a better one out there with her shown from the front, but I can't find it for the life of me.
Secondly, I'm introverted and serious. May, meanwhile, is extroverted and fun-loving. Deep down, I have a more open, fun-loving side to my character that just begs to be let out by the right person. Opposites definitely attract, in this case.
On the subject of extroverts, I know a few of them that kind of rush and make rash, selfish decisions. May isn't like that. I remember one episode in AG where she had to choose between searching for her brother and boarding a boat that was about to depart for a Contest: she chose to search for her brother. That takes heart. Barring some extreme circumstances, she's only going to grow more mature.
I could go on and on about her good qualities, but she's human -- flawed. While she's athletic and has a body to prove it, she's kind of derpy and klutzy: I find all those traits to be attractive in girls. She also has an emotional side to her that comes out when she has a crushing defeat... I want nothing more than to hold her and comfort her in those times of stress.
tldr; May all the way.
My inner autist is out, but I mean every word of it. Is it clear that I've been madly in love with May for ten years? On a scale of one to ten, how much help do I need?