I'm 17 have been smoking for a year and in the last half a year almost two packs a day do i have bigger chances of getting lung cancer?

Quit Now: Quit NOW, before it's too late. Now the increased risk you have done to your body is largely theoretical (although some might argue some permanent harm has already been done). Keep it up for a few more years and we will be able to tell you more precisely how much you are risking your life. Don't start killing yourself until you are at least out of your teens. When UR older, you'll know better.