What a beautiful little girl, congrats.
I have nothing to add to what's been posted, you've received very good advice.
When you do change her food, like Lady Sam said, transition gradually. On the first day of change add three quarters of their old food, and one quarter of the new food. You should do this for at least two days. After two days or so, depending on how the puppy has reacted, add another quarter, so you have half old food, half new food. This should be done for another two days, or more if the puppy is not adjusting well. Then add a third quarter (one quarter old, three quarters new) again for two days or until puppy has adjusted. After that you can phase out the old food completely.
Good luck with your beautiful baby.