Am I prone to lung cancer if I have a strong family history of smoking?

Hello doctor,

I am 29 years old, and I have smoked three and a half packs for years in total. I quit smoking three years ago, and I smoked half pack a day from ages 19 to 26. My great-grandmother on my grandfather's side died from lung cancer at 49. She was a very, very heavy smoker, and so was her husband, so she was always around it. Does her dying early increase my risk of getting lung cancer, or does it not matter because she smoked very heavily, but that was several generations ago? Her daughter, who is my grandfather's sister, is in her 70s and has COPD. She was also a lifelong smoker. Should I be worried even though I just had 3.5 packs all these years? I do not know if genetics were still a factor here. Please help.

Thank you doctor,

I would like to know, on average, how many pack years does someone smokes get lung cancer? I know anyone can get it, but I would like to know on average. Because I heard you are not even told to get an assessment until you have like 30 pack-years and are above 50.