This is the completed room.
This is what that same wall looked like before the redo. When she was 10 her sister and I did this to her room, it matched a pattern that was on her comforter at that time. However that was on a twin bed and she outgrew that so we had to get her a bigger bed, which meant bigger comforter. The walls are a pale, pale lavender with this design on one wall.
First I put on two coats of white paint with primer in it to cover the purple decoration. That took only one day.
This is the part that took 3 days, oh yes, not to mention the day after I put 2 coats of paint on her walls and ceiling, I could hardly move, so it set me back a morning of work. Then I marked the strips with a level, and taped. Before putting the color on, I did what I call under painting. Got this tip on line, I first painted the taped area where the color would be with the white paint so that the color wouldn't seep under the tape, it really helps to make the lines clean.