She'll be keeping things slightly secret at the start (she's fresh off a time travel adventure and Starfleet has strict temporal protocols), but once she realizes things are Very Weird and Not Okay here, he'll likely be one of the first she tells! They can lament about missing space and the freedom of being on a ship. :( But bonus, she'll never press him about taking off his helmet — respecting other cultures is basically Starfleet Rule #1.