I've trained seriously in Wing Chun kung fu and Hung-Gar kung fu; I've done a bit of karate and a bit of white crane kung fu farther back on the timeline, but nothing to write home about. And (disclosure) I'm out of training and have been for several years now.
Wing Chun is far and away the style that meets my needs best; it's a fighting style that emphasizes the speed that you can only get when your body is relaxed, and maximizes the benefits of the "shortest distance between two points" principle. Simplicity, speed, and balance. It's the style that is known for the "one-inch punch", popularized by Uma Thurman in the movie "Kill Bill". My focus wasn't on my clumsiness, although in retrospect perhaps it ought to have been - I needed to address a growing anxiety problem and I wanted to feel scary, physically powerful, strong, competent, able to defend myself. Predictably enough, the mental training was much more useful for that than learning how to throw a devastating punch, ultimately.
If your primary goal in taking up a martial art is managing a tendency towards clumsiness, I would start with the obvious question: why are you clumsy? Is it mostly because you are easily distracted and forget to pay attention to your body while moving around (that's me), or do you trip over stuff and overbalance and stuff even when you're paying attention and trying not to? Actually, even more obvious, HOW are you clumsy? Are you a tripper, a stumbler, a face-faller (me, again)? An overbalancer? A toe-stepper or shin-kicker? I'm not sure about Aikido for you, anyway, I would more go for something that doesn't require mats on the floor (Judo and Aikido both have a wrestling element that I think you would just hate if you have a horror of being stifled). Are you more likely to benefit from a formal atmosphere in the training space or a relaxed one?