I'm 21 yrs old what are the realistic chances of me having oral cancer, been smoking 6-7 years on and off?

Realistic?: Much higher than one who has never smoked. We used to say that one who starts between age 12 and 17, and smokes for 5 years, then never again, has the same risk as one who starts at 25 and smokes daily for 30 years. Risks are multifactorial: include genetics and co-factors. Like crime, if you can't do the time, don't do the crime. If you can't risk the disease, don't do the deed. Best to quit!

Smoking: The risk of oral cancer is there, it may not happen now but may occur decades later and you will be really sorry for not kicking the habit at your young age.

Still Concerning: Oral cancer is devastating. Smoking significantly increases your risk. Other factors like alcohol use and family history are factors in how likely you are to actual get oral cancer. Don't belittle the lifetime impact that even part time smoking can have. There are many tools to help you stop smoking, but the most importantly decide that it's a significant health concern and decide to stop.

Smoking?: Another question would be do you drink alcohol as well/ have you ever used smokeless tobacco. Do you have a family history of cancer. These things are not an additive effect to your risk they are an exponential effect greatly increasing your risk. With everything that is known about cancer and its risk factors today it is disheartening to have so many people simply ignore them. Do the right thing!