Cancer that runs in our family deeply

My mother passed away 5 years ago with lung and possiable throat cancer. Of course cause of smoking. Just this passed November my dad passed away , cancer . My sister is not only dealing with RSD , but cervical cancer , and lung cancer . My oldest  brother found out just this pass October he had spots on his lungs that show cancer. All of us smoke and I am going to try to quit smoking tomorrow . I am 29 years old but I have four children that I do want to see grow up , get married and have my grand children . Right now I am very nervous and I know if I want to live I need to do this. If anyone has any comments to help me get through this All comments are welcomed. All wish me luck!