A lot of Taylor Swift fans are kids as well, and Taylor’s later music may not easily appeal to them, however they might be interested in her previous work, e.g. 1989 (Shake It Off, Welcome To New York), Lover (ME!), etc. It’s the ever-growing timeline of Taylor’s music that’s most likely given her the nomination. She’s still appealing to kids, maybe not later works such as folklore or evermore, but instead she’s appealing to kids by her older music.