Is it normal to go from being able to read without reading glasses to needing them to read by the age of 50?

It happens to most people at some point around 50 or a few years later, so I would say it is normal.

It is common for our eyes to lose the ability to focus on close items as we age.

As a related aside, I have been taking AREDS 2.0 since age 57 for age related macular degeneration and the biggest benefit I have noticed was a big improvement in my night vision. My ophthalmologist confirmed that many experience this.

Yes, as I can tell you from personal experience

Yep and it isn't a sudden thing... it is and we don't notice it, a gradual process until one day it becomes obvious to us.