Left: Alyssa Rice has aged normally like most other ponies, but she’s managed to grow the same height and grow bigger wings as Twilight Sparkle when she became an Alicorn. She still has her Magic Headphones to keep her company, and she still spends time with her friends and family. She has retired from working at the Mushroom Cafe to become a famous DJ, but she still lives there as she considers the cafe to be her home.
Right: Alyssa Rice had grown up to be an Alicorn princess after defeating the final villains with the help of her friends, along with The Squad, The Other Squad, and the Awesome Six. She was crowned as “The Princess of Inspiration” because her music had improved the lives of other ponies. She resided over Twilight’s Castle along with her friends when Twilight moved to Canterlot as the new ruler of Equestria, and she got engaged to Walker Warrior. As Alyssa grew older, she became a lot taller than she expected to be and her mane grew longer, wavier, and sparkly. She sometimes reached out to Twilight for help. Despite her royal duties, she was still the Alicorn of Love and Music, no matter what.
I’m not sure which future version should I use for Alyssa… They both look very pretty.