How many dimensions did the universe have immediately after its birth? I don't seem to remember.?

Unknown. We don't even know for certain how many there are now. There's at least three, but some scientific research indicates there may be as many as 11.

It depends what you mean by immediately. If you're talking about the 1st billionth of a second the Universe was without dimension, just pure energy in the form of a plasma and matter hadn't been created yet. If you mean in the 1st 5 minutes then the Universe would have similar dimensions that it has today, namely length, breadth, height, mass, density and time to name just a few. JULES. PS The 11 dimension theory is related to the theory of membranes and is commonly known as the Brane Theory. It is very controversial and it relates to 3 dimensions of Matter (L.B.W), 3 dimensions of Mass (rest, accelerating,decelerating), 3 dimensions of Time (past, present, future) and the strong and the weak force. JULES

.. 11 dimentions . the universe have after its birth

The one your livin in! The fourth!

what do you mean by "immediately"?