My 12 yr old is having real problems adjusting her body clock after hol in florida 3 wks ago - any suggestions

She is still awake at 1or 2 am and then finds it really hard to get up for school. She is going to bed at normal time but is starting to stress about not sleeping and is getting into a downward spiralMy 12 yr old is having real problems adjusting her body clock after hol in florida 3 wks ago - any suggestions
Try lots of exercise after dinner, enough to really truly tire her out. A mug of chamomile tea before bed will help as well and is safe for kids. Warm milk is a classic, but I don't use it myself, so I can't personally attest to its effectiveness.
No television or computers for the last hour before bed. The screen flicker stimulates the brain and makes it harder to sleep.
If possible, also try eating earlier. It's a way of tricking the body into thinking that it's later than it is. Don't point it out to her.
If it's really bad, consider a brief round of melatonin. In the UK, you can get it via prescription from the NHS. Research it a bit though, because they tend to prescribe high doses. (In my opinion.)
It's difficult to adjust, especially for young energetic kids. Tell her it's really normal and she just has to help it along.
part of the problem is worring about it, she needs to relax
Try having her go to bed earlier. If this continues, I'd suggest getting some sleeping pills for her; talk to her doctor.