I started TTing my DD when she was about 2yrs old. I stopped as I knew she wasn't ready. I then tried again at 2.5yrs, once again she wasn't ready. I felt like I'd failed because alot of our mothers group kids were TT & also DD's friends seemed they were mostly TT. I decided to give her more time. I'm glad I did, I tried again when she turned 3 & there were no problems, she was quite obviously ready.
Some of the mothers group children have gone backwards & are back in pull ups again now but I dont have any problems with DD. Even through her daytime sleep she's in knickers but at night time still in pull ups. (haven't tried knickers at night time yet)
I say don't push her, it sounds to me like she's not ready. know it can be really frustrating for you as her mother but I think the best way to go about it is to try every couple of months & when she's ready you'll know (& so will she!)

Wishing you all the best