お風呂に入りなさい。
Get in the bath.
Take a bath now.
Hurry up and take a bath.
Why don't you have your bath now?
I'm going to take a bath first.
I think I'll go and take a bath.
I am going to take a bath now.
to take a bath―(西洋風に言うと)―have one's tub
I am going to take a bath now.