It doesn't matter if we think the pink is ok - you don't. And that will keep you from enjoying the experience. Probably the 'best' remedy for you would be to rip them out and replace with the yellow. While this will take time, it is so much better than ending up making this a UFO. The upside of it is that you saw this before you put the blocks together. That would have made it a huge correction. For new quilter's, this is a good lesson in value/tone of fabrics. The pink is a perfectly nice fabric, but not the same 'color level' of the others. The yellow just works better. Also a great reason to make one block, stick it on the wall and really look at it.