It's the right time of year and the right age for her to be getting ready to lay an egg. If you aren't already giving her a quality layer feed, I would make sure that she has access to free choice oyster shell.
Some turkeys have crammed themselves into chicken nest boxes while others just crawl into a hidden space such as under a bush or in a bushy fence line. I currently have one that has made her nest in the middle of a tall patch of sweet clover. Once you find her nest site, leave a fake egg in it. Turkeys don't like their nests messed with and if you keep taking the eggs without leaving a fake egg, the hen will abandon the nest and make a new one.
Good luck.