Perched on a gurney at dawn, Kricket Jerná Nimmons, 40, kicked her feet giddily, like a girl on the edge of a pool, preparing to take a plunge. She wore a hospital gown and purple socks with paw prints. Her face was clean-scrubbed — “no lash, no makeup, just me” — and she looked at peace.

“So, this is it,” she said, exhaling theatrically, which is her way.

A Brooklynite by way of South Carolina and Georgia, Ms. Nimmons was ticking down the minutes, as she had ticked down the months, until she would be wheeled into an operating room for gender reassignment surgery. It was a moment she had long dreamed about but considered out of reach, a shimmer at the edge of her field of vision.

Now, though, societal attitudes toward “transgenderalism,” as Ms. Nimmons calls it, were shifting so rapidly that many health plans were overturning their long-held exclusions of transition-related care. Even public insurers were approving surgical procedures that, until recently, were accessible only to those who could pay out of pocket, despite medical consensus about their safety and efficacy.

Seizing the opportunity, Ms. Nimmons was about to become one of the first low-income New Yorkers to undergo a genital reconstruction paid for by Medicaid. In a few hours, if all went well, her body would be aligned with her identity for the first time, and she would no longer be “a chick with a wiener,” in her words, but “a woman in mind, body and soul, before the Lord and before the law.”