Reality
She knew. Deep down, Twilight had known for years. It was obvious, really: how long had Celestia and Luna been alive? Thousands of years and they were alicorns. Yet, how long did the average pony live? Up to a hundred if they were lucky.
Twilight had known for a while, that much was true, but she still thought...maybe...just maybe, if she didn’t think about it, it wouldn’t be true. She told herself that ever since her ascension. She hadn’t had to think about it that often either with all of the evil creatures coming back for revenge and with running a school, and lately her princess duties took up most of her time. She forced it to the very back of her mind, and there it would stay as long as she was busy.
Yet, changes had become more and more evident with every passing moon. It was hard not notice, really. With only seeing her friends once a moon in Canterlot, the changes became blatantly obvious to her every single time. Twilight noticed when Rarity’s hair began to gain a few greys, but she tried to ignore it. Every visit, the princess herself found that she stood a little taller and her hair began to flow just a little more with magic every moon. She noticed the looks her friends gave her, some pitying, some confused, some sad...they would never bring it up, however. The reality was blocked every visit. Twilight was not ready to face it, and her friends never seemed to bring it up, seeming to sense her overall discomfort. That was fine, really. Twilight continued on, ignoring all reality.
It had become a habit. Whenever she saw Spike, she would notice him a little taller too. He had a job as the friendship ambassador at that point, and he was gone often as well. Twilight was not used to such isolation--even back when she was Celestia’s pupil in Canterlot she still had Spike--so she decided to take in a new pony under her wing: a filly that was young and very gifted at magic.
Perhaps Twilight took Luster Dawn in as her personal pupil because of the similarities the young unicorn had to her younger self. Maybe she took her in as a reminder of the past when she was a carefree young unicorn who lived in a library: when her highest stress came from sending a weekly letter to Princess Celestia. Perhaps it was something else entirely. Twilight was still not sure herself. Still, no one questioned her: she was the princess of Equestria after all.
The question had come out of nowhere that day: Luster was maybe thirteen years old, and her questions seemed endless, yet that day’s question stunned Princess Twilight to the core. “Princess,” the little filly began.
“Yes, Luster,” Twilight replied, a small grin adorning her muzzle as she awaited the question, perhaps a little eager to hear it herself. She now stood at nearly Celestia’s height and her mane flowed just the slightest bit slower than her former mentors own. “What is it?”
“How old are you?” The alicorn froze and slowly turned to face Luster Dawn. Her pupil’s eyes were wide with curiosity, and her head was slightly tilted to one side. Twilight’s heart raced, but she forced herself to crack a very forced smile.
“Why do you ask?” Luster frowned, little eyebrows scrunched as she thought hard for an answer.
“I was just wondering,” the filly chuckled, oblivious to the alicorn’s inner turmoil.
“...I am forty-three,” was the whispered answer, and Twilight could suddenly not make eye contact with the young filly. Luster seemed to think about that for a long moment, her head still tilted to one side.
“...you don’t look like any creature I know who is forty-three,” Luster replied earnestly. Twilight’s breath hitched in her throat and she could feel her eyes stinging a little at that. Many would have smiled or even been thankful for a compliment like that, and maybe a few years ago she would have done the same, but now, for Twilight, reality finally came crashing down. Those simple words--the very simple question--had stopped the princess cold.
The alicorn swiftly turned away, shutting her eyes tightly. At that moment, time itself seemed to slow and dread began to fill her chest. Her ears pinned back and the princess forced herself to take a slow, calming breath, a technique Cadence had taught her all those years ago. Finally, after a long while, the princess finished, “...no. I suppose I don’t, do I?” Twilight let herself sit down onto the throne room floor. Only when Luster had left the room did Twilight let the tears flow. The little filly did not need to see her like this: she was a princess and she would not burden her pupil with such feelings. Luster was far too young for that. Twilight then lit up her horn and swung the throne room door shut. Then, she began to walk slowly. She looked at all of the stained glass windows as she did so, each one recounting some major Equestrian event, most being of her and her friends…just the thought of her friends, hair greying wrinkles beginning to form on their faces made her vision unfocused and blurry with tears. She couldn’t picture a life where they wouldn’t be around, she didn’t want to. Yet, with how fast the years seemed to go by lately...she just hoped that future was far off. She remembered Celestia’s guidance all of those years ago when Twilight herself was Celestia's pupil and realized that the alicorn had been alone for a thousand years, without even her sister for company. Luna had been banished for a thousand years, and Twilight did not remember Celestia even mentioning any friends she had during the time her sister was locked away. The very thought of being alone that long made Twilight shake her head.
“How did Celestia handle it?” Twilight thought to herself. “When reality came crashing down on her?”