Don't know if I have cancer yet & I'm thinking of getting life insurance today. Is it lying if I tell them I'm healthy ? Will know in 7 days?

That is a tough question. They may never know. But the insurance company might know. You will soon find out. The life insurance company runs your doctor medical record and your drug history so anything recent they will find. But no one here would know for sure. Just wait and see. But if your telling them your healthy today and you might not be, you might not be covered. Worse case they will not accept you and will refund all your money back to you. So, no harm done. good luck.

Wait to find out. They can cancel your policy if they find out (and they will) that you wrote a policy while knowing that it's possible that you have cancer. After all you can't be turned down for preexisting conditions.

If you have already seen a doctor or had tests, that would invalidate insurance.

If fraud is suspected, then they would cancel the policy so waiting is prudent

i would wait the 7 days