What Are The Chances Of Leading A Healthy Life If Smoking Is Stopped?

I am twenty years old. I have had occasional cigarettes since I was 16, but I have been properly smoking for exactly two years, one month, and four days. I have rarely if ever had any less or more than a pack a day. I eat a small box of blueberries (about 1/4 of a pound in weight,) every day, rarely drink excessive amounts of alcohol. My diet is such: Breakfast - glass of milk, cup of coffee, three fried eggs, two toasts. Lunch - a few small mandarins, and stirfry veggies with rice. Dinner - two steaks and some mixed vegetables. I do not exercise properly in the gym; however, I do not go a day without large amounts of pushups, and long walks to fill my lungs with clean air. I get about 6-7 hours of sleep a night. Assume I quit now, cold turkey, and do not touch cigarettes ever again, and continue my relatively healthy lifestyle, is there a chance that my risks of cancer will drop? Is it already lowered due to my lifestyle?