D.M.
I would try the opposite of what you're doing - don't remind her at all. She will go eventually, and if she has an accident, I'm sure that would be the last one, because what 7 year old wants to pee her pants? She needs to think on her own at this age. Don't remind her for a week and see how it goes. What you're doing is "enabling" her, meaning she lets you take control, so don't do it, and let her take control of her own body. She can't hold it forever.