It's okay. As D. D. says, there's no manual. It does make us think about what our parents did with us at that age (or didn't do). But that also can open us up to the realization that we just have no idea how our parents felt - which is a good window into how clueless our own teens are about us.
I think parenting is a process. You try things on, you make more gradual moves than sudden ones, and you absolutely have to have enough confidence to stay ahead of the teen. That doesn't mean you know everything; it just means that you are absolutely certain that you know more than he/she does!
Recognizing that this is an in-between stage is part of it. You'll find that your teen wants tons of independence and very little responsibility. So that's the first tip-off that he's not ready for as much as he thinks. What we found very helpful was to attach a new responsibility to each new privilege. So, being allowed to stay home alone means being responsible enough to, say, be in charge of his own laundry (wash, dry, fold, put away). Being allowed to go to the movies or the mall alone, or to have a cell phone, or to have unsupervised internet privileges (well, moderately supervised anyway) means X, Y and Z get added. He always wants money? So you get him a back account (they have no-fee accounts for teens) and you let him start to learn to manage it rather than just hit you up for $20 every time you turn around.
You'll find this a very helpful custom once he's 16/17 and wants to drive! You'll already be in the habit of expecting more of someone who is constantly telling you that he's not a kid anymore and is trustworthy. So, you basically agree with him: "You're right, I agree that you are capable of so much more than you were before. So you'll have no problem being more responsible and learning new skills you will need when you leave our house as an adult."
My son's college roommate was an extremely bright kid who never used an ATM machine until his senior year because his loving mom would drive 4 hours each way to bring him cash every 3 weeks. He had no idea how the recycled paper, plastic and cardboard got from the dorm room to the collection center on the first floor because he had never, ever been expected to carry his own stuff out to the garage bins when he lived at home. He certainly couldn't wash clothes, iron, or cook. So start giving your son a new skill at least every 2-3 months, and you'll really have a well-rounded kid by the time he heads to college or the working world! As you start to measure his progress, you'll feel more confident about your parenting.
And based on some recent questions on Mamapedia, if you haven't had the sexual health talk (or, much better, a series of them), START! They need the facts of sex and reproduction, but they also need to learn that "No means no" before they start dating.