C.B.
If she's interested, go for it. Put some big girl panties on her one morning and tell her that she's a big girl now and should pee and poop in the toilet all the time. she will probably have at least one accident, but if she's that interested when she sees the consequence of peeing in her panties, she'll probably go straight to the toilet. It's one thing to push a child who's not ready, but it's another to ignore the signs of a child who is ready. You will probably find that she does a lot of things earlier than her older sibling because she's copying her sister and she wants to be a big girl just like her sister. Don't hold her back waiting for the time you did things with her sister; she is her own person and will be ready for things at her own pace.