Stroke's Color and Weight isn't changing in Illustrator 2018

Hello, Adobe Community!

I'm using the Pen Tool to trace my drawing that I scanned, and I'm having trouble changing my strokes in Illustrator.

Whenever I select the stroke that I want to change, the stroke's size, color, fill color, or style doesn't change.

For example, let's say I have a stroke that I want to change to a Size 5 pt.  When I change it to 5pt, the stroke's size doesn't change on my screen.

The same thing with color.  If I want the selected stroke to turn blue, it won't.  It will just stay black. 

Same thing with the stroke style and fill color. Nothing happens.

I just renewed my Adobe subscription and updated my Adobe apps today.  I've also used Adobe and pervious versions of Illustrator before.

If it helps my Mac has macOS High Serria Version 10.13.5.

Thank you in advance for everyone's help!