How long did it take people to read after invention of the printing press?

People could read long before the invention of the printing press. People were reading and writing in ancient Egypt four and a half millennia (that's 4500 years) before the invention of the printing press around 1500.

But, and here is the key point, although some people could read and write, not a lot of people could. The printing press made printed material available to many more people than had access to manuscript copies of things before. And that meant that more people had an opportunity to read, and therefore to learn how to read. Thus the number of literate people rose considerably in the centuries following the invention of the printing press.