Twilight somehow got through the day without using all her energy. With her big brother, Shining Armor, by her side, it was easy. He held her back every time she was about to go overboard with excitement, but expertly kept her occupied the whole day long so that she wouldn't get anxious while waiting.
The siblings coloured and played checkers, they read books together and helped their mother make snacks and do the dishes. The day was easy to pass with her family by her side, and as the evening celebration came closer, Twilight knew this was the best day ever.
There had been a leisurely pace to the day, but once the celebration festival began, everything began to move by so quickly. They ate and played on the rides and games that were set out for the celebration while they admired the effort that had gone into decorating the town square of Canterlot. Everything was a whirlwind of joy in celebration of Equestria's princess and the gift she gave them by raising the sun every day.
Dawn came, and it was time for the raising of the sun. The crowd pressed in, moving as one towards the podium where Celestia would raise the burning ball of light into the sky to begin the first new day of the new year.
Twilight had never felt so excited. The anticipation welled up in her, but as her brother had said, she kept it down to conserve her energy.
As the crowd pressed tighter around them, Shining and Twilight were pulled away from their parents. The little filly looked nervously to her brother, but he just smiled down at her. The sounds of the crowd drowned out his words, but Twilight could see he was telling her it would be okay and they would find them later.
As the time for the sun to rise drew nearer and nearer, Twilight was pulled away from her brother. She tried to push back against the flow for a panic-stricken minute, but remembered that this was her home city of Canterlot, and she would be able to find her family at the conclusion of the celebration.
Twilight looked towards the podium, but she was too small to get a good view from so far back in the crowd of ponies, so she began picking her way forward, catching the odd disapproving glare from mares and colts as she did so.
She managed to squeeze herself right to the front of the platform where her princess stood and waited. The lights in the town square suddenly went dark, and Princess Celestia lowered her horn.
The entire crowd was completely silent, awaiting this special moment. The moment Twilight had waited her entire life to see. The royal guard on the stage blew their horns in a celebratory tune and Celestia finally stepped forward, wings outstretched and her brilliant mane flowing behind her in regal beauty.
Twilight could feel the grin taking up all of her face. The excitement could be felt in the air through the entire crowd.
After looking out over her gathered subjects for just a moment, Celestia closed her eyes and her horn began to glow. She dropped her wings gently along with her head and then suddenly propelled herself into the air with a flap of her wings.
Twilight couldn't even blink as she watched the princess rise into the air, the sky brightening in a pink glow behind her. When she reached the middle of the sun monument, her body was only a shadow in front of the brilliance of the newly risen sun, it's brightness covering the gathered crowd of ponies as they gasped in awe.
When their princess looked down over them once more, a massive cheer came from everypony surrounding Twilight. The joyous screams and stomping of hooves was deafening, but Twilight didn't join with them. She was too awed to do more than grin up at her mighty princess.
The raising of the sun was the single most amazing, most wonderful thing she had ever seen or could ever hope to see. The princess was majestic and incredible; her alicorn magic had pulled the sun into its position in the sky, bringing light and heat to every pony in Equestria, and Twilight Sparkle had been there to witness it.
The little foal felt a surge of inspiration and conviction. If alicorn magic could do that, unicorn magic could certainly do things that were just as wonderful, and so she, Twilight Sparkle, was going to be able to such things herself.
In a loud voice, Princess Celestia announced the Summer Sun Celebration to be over for another year and trotted regally from the stage. The crowd began to disperse, but Twilight stood in her place, staring up at the sun. It would be hard work to use her unicorn magic for something so magnificent: Twilight had read a bit about her magic and its application, and she knew it required a lot of study, but that was what she would do.
She looked into the beaming brightness of the sun and vowed that she would show all of Equestria what incredible things unicorn magic could be used for.
Twilight was still staring when she felt a hoof on her shoulder. She turned her head to see her big brother's grinning face. "Did you see it, Twily? Did you get a good view?"
"Yeah," Twilight said distantly, not looking directly at her brother.
Shining Armor frowned down at his sister, "Did you not enjoy it?"
"No, no. That's not it." Twilight finally looked her brother in the eye, grinning from ear to ear. "That was the most amazing thing I've ever seen. The princess is so ... so ... brilliant! And one day I'm going to be able to use my magic as well as her, Shining. I will." She nodded, as if to affirm her promise/
"That's great, Twily." Shining Armor looked genuinely impressed. "I know that you'll do great." He looked to the left and right. "Well, we should go find Mother and Father and head home. I think it's time a certain little filly had her rest."
I referred to the Summer Sun Celebration as the beginning of the new year. This is not canon. As far as I can recall, there hasn't been a mention of a Pony new year, so I thought the summer equinox (the longest day of sun) would be the best place to put it. It kinda is a new year celebration, since it happens once a year and everyone stays up all night to look at the sky (:P) so there you go, new year it is. Argue if you want, I'm open to Pony canon. :)