If the universe is infinite now, it must also have been infinite during it's earliest phase greater than t=0. If the universe is finite now, it it must also have been in\finite during it's earliest phase greater than t=0. What happens at t=0 is undefined since the GR equations for the universe have a singularity at t=0.

One of the comments mentioned the finite "visual" universe, also more commonly called the observable universe. This is always finite independently of whether the (whole) universe is finite or infinite.

Sometimes you may see in an article the term "universe" (carelessly) used when the intended meaning is "observable universe".

If the universe is infinite now, it must also have been infinite during it's earliest phase greater than t=0. If the universe is finite now, it it must also have been finite during it's earliest phase greater than t=0. What happens at t=0 is undefined since the GR equations for the universe have a singularity at t=0.

One of the comments mentioned the finite "visual" universe, also more commonly called the observable universe. This is always finite independently of whether the (whole) universe is finite or infinite.

Sometimes you may see in an article the term "universe" (carelessly) used when the intended meaning is "observable universe".