Vicodin..? Help please?

Ok, so I went to the doctor today and he prescribed Vicodin for me.. I am a little worried about the dosage because the pills are huge and he didnt ask me any questions about diet, height, weight, or anything. I am 15, and the Vicodin says Watson 349 on it. What effect will this have on my body if i weigh approx. 115 pounds and am 5'2"? How many pills should I take for the desired effect of being blissfully unaware of the world around me? lol, but seriously- how many of these am I supposed to take for my age and everything without OD, but enough to have a good effect?