You will probably get more advice in the Training section of the forum.

Also, since she's going on the mats, have you tried laying down pee pads on top of those mats she goes on? Or are those "mats" actually the pads you are already using?

Also, for the long term, was it your intention to just have her only do her business outside and no more mats? Maybe walking her first thing in the morning when you wake up and then every hour afterward if you have the time as I'm assuming she's still young. Then gradually increase the time in between walks until you're down to maybe 3 walks a day. That might help.
Good luck with your little one! She sounds like such a sweetheart.