To train or not to train?

My oldest, a girl, will be 3 in June. Almost 2 months ago we started toilet training because she really liked the idea of flushing the toilet and big girl undies. For a week, maybe two, she seemed to be doing really great with less accidents every day. After that it was like she totally lost intrest. She used to get temporary tattoos for going...all of a sudden she didn't seem to care about them. We've tried what seems like everything. Potty dances, treats, stickers, tattoos, stories, favorite movies...everything and nothing seems to intrest her. We've tried to leave her in wet pants for a little bit but she doesn't seem to care at all.She has a 6 mth old brother...which could make a difference (reverting back to baby habits)?? But at the same time I babysit in my home so there are lots of "big kid" examples and even when we remind her of that and ask if she's a big girl she says yes but still doesnt want to go. She doesn't (and never did) tell me she had to pee (shes delayed in speech) so I take her every 30-45 mins and she pees a little and will say 'done' but then can wet herself as soon as 10 mins later. She allways says no when I ask her to go, and lately has been putting up quite a fuss if I try to take her anyways. I hate it being a battle with her and I'm getting frustrated because its been over 2 months and she goes through almost her whole pants/undies arsenault per day. Is she just not ready yet? Should I take a break and start again in a few months? Or will that give her the "I won" feeling? Any help of advice is super apreciated! thanks in advance!