I am a new yorkie owner. Actually I am a new Gammaw

I bought my 13 year old daughter a yorkie two weeks ago. The breeder had her on Science Diet but thanks to all of the wonderful information that I have learned from this site I switched her food to Canidae. I gave her one cup of food on Saturday and she has only eaten about 1/4 of it as of this morning. Today I mixed it with water to soften it some and she ate a small portion of it.
I am very worried. Can anyone please give me some advice as to what I should do to get her to eat. She weighs 2.3 lbs and is 13 weeks old.
Thank you so much for any information you can give.
Nicki