How to keep lo curly hair?

My daughter is like an exact mini me and she has curly hair right now like I did when I was her age (2) but my hair went straight sometime between 2 and 4, idk how tho.. the foster parents that I had at the time died so I can't ask them and no one in my family knows. So does anyone have any ideas on how to keep her hair from going straight? Her curls are so beautiful