first of all,
Second of all, I think 6'4 is pretty tall!!!
Thirdly, just because you have no health issues now does not mean you will not acquire them if you don't change your lifestyle.
As far as "losing yourself" goes, going through a dramatic lifestyle change takes time and effort and yes, you may find yourself changed a little bit. But you may find yourself to be more confident, stronger, and yes, more attractive. I know how you feel about not knowing how you will appear at a healthy weight, I'm in that boat myself.
I think your worries are completely understandable. These are the things we can actively see change about ourselves. The pant size, the differences on our physical body. It's somewhat difficult to put the health aspect into perspective if you're not aware of just what's going on inside of your body.
Your reasons alone are reasons enough to get started and you may find somewhere along the way that your weight loss priorities have changed slightly. It happens all the time.
As far as hanging skin goes? I'm not gonna lie. You may have some. But that's why it's important to include plenty of exercise in your new lifestyle.
Good luck!