"J'ai décidé de me doucher."

Translation: I decided to shower.

[jamaud]

It is more common to say 'I decided to HAVE A shower' otherwise there is a question hanging of 'what are you showering? ... plants with water, your children with love, your partner with kisses...'

[n6zs]

Without further reference, there will be no confusion about it. Some people say "take a shower"; others "have a shower"; still others just say "shower". For English speakers, the expression is clear. The action of the French reflexive verb is on the subject.

[uneclown]

Why is the de necessary?

[doublelingot]

to decide to do something = décider de faire quelque chose

• I decided to write her. J’ai décidé de lui écrire.
• I decided not to go. J’ai décidé de ne pas y aller.