Aside from getting her a quick check at the dr I would accept this as not abnormal.
Sorry, probably not what you want to hear.
before having my kids, I really though all children could and should eat well, sleep well, play well, and certainly be TT. Anything less was an indictment on their parents.

I could have posted your exact post at 3.5 yrs for DS1.
And at 4 years.
And at 4.5 years.
He ran through phases or being totally in control and then constantly wet. Even regressed with pooing at one point. And my emotions went through it all too. What did I do? What was wrong with me/him?

But he is 5.5 now. Totally toilet trained (although the seat takes a hammering some days!) day and night and its just not an issue anymore. He did get it. Eventually. And I hate to admit that I just had to wait. There was very little I could do to help him along.

DS2 decided at about 20 months that he was no longer going to wear nappies and he ttd himself in a day. Day and night dry. Man, I thought I had hit the jackpot. Well, he's 3.5 now and somedays he's accident free, somedays not. And hes no longer night dry either. And there is very little I can do about it but just gently try to help him when he needs it. Distraction, laziness, embarrassment, whatever the reason. It's not always possible to answer.

I know now im not alone. Some children are ttd early and completely. Some, many, aren't. My only advice is try to stay calm although I agree it can seem frustrating. It will pass.