Does anyone have experience with the cut-off date for TK?

I just called the school district phone number with that exact question. They said it is a hard date but worth a call if your child is just missing it by a day! Mine was a month after the cut off. The person I spoke with had a daughter who was 2 weeks after the cut off and she had to wait a year for kinder.

You didn't mention which district you are in, but we registered in WCCUSD and the cutoff date was determined by the registration software. I had to upload a birth certificate at the time of application. The computer then sorted the TK and K kids into the right class based on their birthday. Since TK is optional, and so many parents within the date range want in and cannot enroll due to capacity, I doubt they would let your daughter enroll. My daughter also did not fall in the enrollment dates for TK and was sad when her friends did get to go. In our local school, they have 24 spots, and the principal said usually 100 eligible families apply. 

Now, if you are in a different county, they may still have a human who determines the cutoff. There may also be less of a demand where you are. 

Private schools, (I have heard from friends) are much more flexible on dates. 

My son was born on Dec 7. I called OUSD before he was ready to start school, and there was absolutely no flexibility. He did another year at his preschool, which luckily had a good "pre-K" program that satisfied his curiosity. 

It depends on the district.