Taylor Swift showed off her more mature side in a daring cutout J. Mendel gown on the red carpet at the ACM Awards in Las Vegas this evening. It's been a busy weekend of honors for Taylor, who accepted the Big Help blimp at Saturday's Kids' Choice Awards in LA. Michelle Obama actually presented to Taylor during that show, and the two first daughters, Sasha and Malia, got to come along for the fun. Taylor is up for multiple awards at today's show, though; unfortunately the fan she was supposed to have along as her date was unable to come at the last minute. New Jersey high school senior Kevin McGuire invited Taylor to his prom, but instead she planned to bring him along to the ACMs. Sadly, Kevin, who is battling leukemia, was admitted to the hospital on Friday and couldn't make the trip, though Taylor tweeted that she'll make it up to him in another way.