God's Existence

I am told that God has neither a beginning nor an end? Let's assume, for the sake of argument that God has been in existence for more than 750,000,000 (million) years? Now, if I live as long as 75 years on this earth, how much time, in ratio, do I have to end up as a saint of God; or, as the case may be, to end up as a sinner against God? Would you believe that, by a simple arithmetic, I have much much less than 7 and a half miliseconds long to carry out either of the silly infantile task! Poch Suzara