I wish this post had been up before I got braces about 6 months ago, because I had concerns about those same things. Additionally, I am pretty young, and I was worried braces would make me look like a little girl. And I wear glasses and was afraid I'd look like "Ugly Betty" and my boyfriend would recoil in horror from my ugliness. Worry after worry. I even took myself out to a "last supper before braces," and cried the whole way through.
I had to have 4 teeth extracted to even get started, and I had big painful gaps. They had to give me "turbos" which made it so I couldn't chew for weeks. If it hadn't been for the fact that once the teeth were pulled, I couldn't go back without looking like a jack-o-lantern the rest of my life, I would have had them taken off without a second thought. Frankly, it was absolutely miserable. AND YET, it was a very, very good decision. Even though I wanted to punch everybody that told me it would get better after the first few weeks, I'm here to tell you that it did. After 6 months, there is a huge, visible difference. I already feel so happy with the changes. My boyfriend still likes me. And most importantly, this will help my teeth and gums remain healthy well into old age. So yes, they do work at any age. Go for it. It won't be fun, you'll miss taffy, but I bet it will be worth it.
ETA: No, I'm not saying people with braces actually look ugly. I'm saying I was being irrational and silly. And kind of a baby, to be honest. LOL