I am a 22 years old woman. I can take a shower with the son of my friend? He is 5 Yeats old.

It's important to consider the context and appropriateness of the situation. If the shower is private and your intention is to help the child with bathing in a safe and appropriate manner (like helping a child get cleaned up after play), then it might be acceptable as long as the child's parent is aware and comfortable with it. Always prioritize the child’s comfort, safety, and the feelings of their parents. If you have any doubts about the appropriateness of the situation, it’s best to discuss it openly with the child’s parents.