I'm a firm believer in the idea that no matter how much effort we put into picking names, it really doesn't matter in the end as long as it's something within the boundaries of "normal" (i.e. doesn't raise eyebrows when read out in a list of names: e.g. "Peter, Sarah, Kyle, Ryan, Laura, Sparklekitty, Daniel - er, Sparklekitty? WTF?"
Kevin is one of those names that fits in. As you mention, it's not your favorite name but you do have some sense of connection to it. I'd stick with it - changing it again seems like a headache you don't need, along with (perhaps) unwanted attention.
In the grand scheme of things, very few people get to choose their own names. They're stuck with whatever their parents decide to call them, albeit with a little leeway for nicknames and suchlike. And in the grand scheme of things, people don't think much about their names - they're called what they're called, and that's that. There are a few hideous names out there, but most sound normal and "fit". And in that sense, we're rather lucky to be able to pick our new names for our new genders. But that, I think, causes us to put undue significance on the very ordinary task of selecting what to call this new person. I suspect that most parents pick names they like, rather than names that have this huge, deep meaning or personal attachment.
I'm not a huge fan of my birth name (which is male - ugh), but I lived with it. It's one of those normal names that has no particular meaning - it's just a way of identifying me in a group of people, just as 99% of people's names are just a way of identifying them in a group of people. It's a functional word, not a descriptive one. So I guess my advice is to not spend too much time on this. Your name is merely a practical way of distinguishing you from everyone else. If it does that job, then it's a good name. As long as you recognize it as you when someone calls out, "Hey, Kevin!", then you're good to go. (And imagine the hassle of re-learning your new name and getting used to reacting instantaneously when people use it...)
You can always use your favored name unofficially - have your friends and family use it, just as they would any other nickname.
But that's just my opinion. My children's names were picked out because my wife and I though they were pretty names. My wife picked my female name for me because she thought it was pretty too (much as it's not what I had originally wanted to call myself). I might not
love the name she picked out, but it has some significance because she picked it, just like you originally picked Kevin.
Not sure that rambling helped, but I'm not convinced that having a new name will make you any happier. What's to say that your new name won't wear out six years down the road?
To answer your other question (and I shouldn't, because it might encourage you to change your name after I've explained why I think you shouldn't), to me you look like "David" - a strong, straight-down-the-line, timeless male name. Kevin sounds a bit 1980s to me. The Davids I know are nice guys, sensible, friendly, reliable. It's not a name I associate with anything negative whatsoever.
