I have no idea if I have pictures in my photo stream . How can I find that out?

Look for the My Photo Stream album on your Apple devices as described in the instructions in Information about the My Photo Stream shutdown - Apple Support

If you don't have that album or there are no pictures in that album then you are not affected by the shutdown.

In the Photos App, select Albums on the bottom. If you do not have an Album titled "My Photo Stream", then you have nothing to worry about.