I smoked for 7 months when I was 16, then I quit cold turkey. My mom did end up finding out and offered help, but I refused nicotine patches and nicotine gum, and while my withdrawal was total shit, it was very short, only 5-6 days. If I had patches/gum, it's would have been a month or two. You need to go without nicotine as long as you can, when you're in withdrawal and you put any nicotine in your system, it will only make it worse and take longer.
Now I'm 17, I started smoking again after I was nearly killed in a motorcycle accident. My bike was totaled, I broke my arm, my back was injured, I needed some way to cope an yeah. I only smoke 4-6 cigs a day though, which was my pattern when I was 16. I don't know how much you smoke, but by the sound of it, you're probably smoking a pack a day or more.
Here's what worked for me:
-Get rid of ALL your cigarettes. Even if you think you can hold your temptation, two days later you won't. Trust me.
-Don't hang around anyone that smokes until your physical withdrawal is over. The smell or just seeing it will induce a craving.
-When you go to the gas station to get gas, don't even go inside. Just use a card at the machine if you can.
-Tough out the withdrawal and don't use patches or gum, although since you're probably a more heavy smoker I stand to be corrected here.
It was easier for me because since I've always been underage, I can't legally buy them and it makes quitting easier. But stay away from sources of tobacco/nicotine until you get out of withdrawal.