Well, that is circular. The premise of the argument is that a necessary being is possible, which is not certain. You then proposed from that premise that a necessary being is possible.
This kind of "logic" is why religion and logic do not mix. Religion is not logical. It is not impossible to know if it is possible. We just don't know that it is possible. Evidence points to the contrary, but it will never be possible to see the entire picture. Therefore, in spite of the evidence, I have to say that we do not know if it is possible, though it seems awfully unlikely. At any rate, the premise is false, no matter what. The given information does not support it. Thus, false.
This kind of "logic" is why religion and logic do not mix. Religion is not logical. It is not impossible to know if it is possible. We just don't know that it is possible. Evidence points to the contrary, but it will never be possible to see the entire picture. Therefore, in spite of the evidence, I have to say that we do not know if it is possible, though it seems awfully unlikely. At any rate, the premise is false, no matter what. The given information does not support it. Thus, false.