Toddler fingering...and using only one finger

Hello,

We started the 24-36 lesson plan yesterday. My daughter is trying the finger exercise, however, isolating fingers are a bit troublesome for her. She does recognize do, re, mi etc...and can identify them. Now, my issue is that while looking at gentle piano and trying it out for myself with my right hand, she said she wanted to try it. I let her and to my surprise, she was able to do it, while calling out do, re, mi etc... (sorry, I don't know the technical term). Although, she only did it with one finger, her pointer, on her right hand. My question is, is this something I should let her try again? I don't want to do anything incorrectly. I also want to discourage her in case it has a negative effect. Did make a mistake by allowing her to try this? Any suggestions/advice? Thanks so much.