My daughter transitioned to one nap around the same time, and it was the same thing with her - the second nap just wasn't working. She didn't cry, she just stayed in her crib and waited until I came to get her. She also slept fine at night. I think as long as your little one is getting enough sleep at night, and she's not cranky during the afternoon, her body is just naturally telling her that second nap isn't needed.
You can move her single nap so that it's a little later in the day, like after lunch. That worked great for me. When my daughter turned 3 in April she was already losing her only nap (the time change in March killed that!) and she's been fine without it since then. She just goes to bed earlier (around 7-7:30) and sleeps about 12 hours. Kids kind of just let you know what they need and as long as it's working I wouldn't think twice about it. You'll be on a new schedule after a day or two and you'll probably find that it works better for you anyway. Good luck, it sounds like you have a great little sleeper!