Can I shower with my Apple Watch?

Firstly the watch isn't and can never be waterproof,it is water resistant.

About Apple Watch water resistance

This is a personal view but I would never wear a watch in a shower,it's been proved that over time shampoo,shower gel,soap and other acidic substances reduce the water resistance of the watch.

I'd go further than fieryjack's advice - an acquaintance ruined his Apple Watch by showering while wearing it on his wrist.