Is it ok to smoke?

Nope. Any amount of cigarette smoking is considered dangerous. And each cigarette shortens your life by seven minutes.
No. You must of heard multiple times that it is not ok to smoke. Do you really think that any of the doctors will give you a different answer? Smoking causes multiple problems to you and people around you, it alters your genetics on molecular level making you much higher risk for multiple types of cancer, it scars and destroys your lungs, it affects your brain, your cardiovascular system, etc.
No. Smoking has been strongly linked to heart disease, lung disease and many types of cancers. Second hand smoke exposure also causes significant illness, particularly in children. No it is never “ok” to smoke, if you currently smoke, there are many resources to help you quit. The american lung association is a great place for more information.