Turn her away. She will not forget anything you have taught her. A quick refresher course when you bring her back into work and she should be fine.
She will be able to mature more, grow and strengthen.
On more than one occasion I have had horses that were backed and lightly ridden as youngsters and then left of a variety of reasons and started much later and they were fine.
I just restarted a big mare that was eleven years. She had been a brood mare from the age of four and then lightly backed. She was absolutely fine and had not forgotten anything.