Starting the stripes

I've decided I've gone far enough in the pink pattern so I'm switching to stripes.  I had a brainache moment when I bought the yarn and didn't buy enough in one colour to do the whole cardigan so I'm striping the bottom.  It strikes me that this is just one of the ways an idea in my head is modified before it becomes a finished garment.  I bought the yarn online and I'm still not convinced that colours are super good together.  Perhaps I will be sure when it is finished.