Is the universe infinite

Im afraid no one knows an answer to this so far.
All that we know about the universe is very very limited, we dont really know where it starts and where it ends. However we know that the universe is expanding, so there is no really direct scientific answer to your question.

The holiest of holies (the big bang) requires a finite universe, scientists will continue to find evidence of objects of mass at impossible distances, they will explain these as other universes in close proximity to our universes bubble. It will be called multiverses, seriouslly I think you can expect the big bang theory to die like the catholic churches dogma as earth being the center of the heavens. One day the universe will be considered infinite in age and size.

There are a lot of geometries proposed for the shape of the universe, some are finite some are infinite and we do not have definite proof. After all our universe in expanding with time. Understanding the geometry of the universe may require high mathematics and physics, the Poincaré conjecture which was proven by Gregory Perelman could ultimately define and explain the unknown about the shape of the universe and whether it is finite or infinite.

The observable universe is finite in size.

The universe that extends beyond our horizon, may be infinite, or it may be finite but unbounded.

Either way, it is incredibly large, and has no edges, no borders, no center, no "boundaries" of any kind (hence the term, unbounded). Sort of like the *surface* of a sphere. Only increased one full spatial dimension.

That's debatable. There are some theories that state the universe is a given size and will always be that size, and there are some that state it is ever expanding. Infinite would be poor word choice to describe the size of the universe though since it is a given size at this moment, we are just unsure what that size is.