he doesn't want to seem like a baby by having to be in at a certain time.
I know what you mean. My wife and I talked to our son about his curfew, and the three of us agreed on a time. This way, he does not tell his friends "my parents are making me come home at 12". He just says he wants to be home.
When the teenage helps make the choice, they feel more like an adult.
-Mike