Immortal?

After returning to the castle in canterlot, Twilight finds it difficult to cope with her new alicorn life style and her own mortality

Changed from the Unicorn of old, Twilight Sparkle comes to terms with being the ever esteemed Alicorn as granted by her completion of a new spell passed down by Star Swirl himself. However not all is sitting tight quite yet. A nagging feeling plagues Twilight, about her own mortality.