Now the question is does she have discriminating tests for quilt blocks? If not how complicated and large donyou want to go? I have done a very very complicated bed quilt for my dd and now am finishing up a dnp cut on differently. There are thousands of ways to go. Go out and pick up two purple fabrics that you a love and think she will like the go from there once you have a couple fabrics you can get an idea of how many more you will need for what ever pattern you end up with. I found this works well because you might have a fabric that works better in one pattern than another. This is just me though.
As for simple patterns for an older "toddler" I would say a dnp or rail fence. If you want to get more complicated there is one called summers sun on quilters cache. I love it for little girls. I made it for my dd as part of a bigger pattern for my DDS bed quilt. It can look like a flower when you are done depending on fabric placement.