Yeah, i'm in Europe too. This is totally normal to me. I would shower with my kids any age we both felt comfy doing so. I shower with complete strangers at the gym and sit nude with strangers of both sexes and all ages in the sauna, so to me it is nothing at all.
I think all children begin to want privacy just around when puberty hits, i was about 10 when i suddenly began wanting to dress in my room instead of in front of the fire while my parents had breakfast. My folks never pushed it. A child seeking privacy is one thing, a parent inflicting it is a form of shaming i am WAY less comfortable with than nudity.
FWIW i was sexually abused by a male member of my family for 7 years. The form of the abuse was not that he had showers with me. It was that he had sex with me. If there is no difference between a shower and sex in your mind then either your sex life is moribund or your showers are VERY exciting.