M.M.
well it seems that you are working to hard. there's a great book out there called by an author w/ last nome of Faul. very short easy read but you may find it helpful. Basically it just says have potty time 2 times a day where you tell her its time to potty then just take her there and basically let her direct the rest. If she's asking for a diaper or waiting to pee for the diaper you should give it to her b/c its a comfort thing. those were some basic things in the book it was very laid back. i think it was called "it's time to go potty" by Faul.
In my own personal experience they are going to be ready when they are ready. Every 20-30 minutes seems like too much but maybe 2x a day and let her come with you when you potty and tell her you are going pee pee in the toilet. My son was potty trained at school b/c everyone else was doing it a month or 2 before he would be potty trained at home and my stressing about it didn't improve but one day he just started going at home too.
good luck