I have a strong craving....?

...for cigarettes. I dont know how. I've never smoked a day in my life and I also know that they can cause a boatload of health problems. But every time I'm around someone who smokes I have the strongest cravings. I'm only 17 btw. My dad used to smoke but he was rarely around me when he smoked and eventually stoped when I was 5. My aunt smokes everytime I see her. And my friend does too but everynow and then. And another weird thing I love the smell. It smells so good. What does this mean?