Except that neither creationism nor current cosmology deals with infinity, and both postulate definite beginnings.
Is infinity a reality in your universe? Once one accepts infinity as a reality, he can introduce both definite beginnings, or no beginnings at all, into reasonable discussion. Even a simpleton like me knows that.
If you wish to reject infinity as a reality, then please bear in mind that it is YOU who will wear the label of "anti-rational" in that regard and not creationists.
But you are not altogether anti-rational, or I could not even communicate with you. By and large I consider you and all evolutionists to be more than decent examples of intelligent design, but I don't think my opinion of you has much to do with your concerns.