October Novel Prep Challenge

When the time came to work on the first Contest Round, I had an idea all prepared and looked at a good resource on how to write a short story. However, a problem soon arose as soon as I started typing: I had no idea how to organize my words into a cohesive piece. I could be overthinking it, so maybe you guys can help. The first contest may have concluded but the topic still seems so interesting to me.

Here's the synopsis from my Book here on WdC:

Throughout Sebastian's childhood, other nobles criticized his right as heir to the Esout Empire. Sebastian didn't completely understand why back then, but it hurt him to hear how people didn't like him. His siblings were permitted to be around him and were even encouraged to play with him. Sebastian's favorite playmate was Oscar since he was around the same age as he was.
One notable event in their relationship occurred during Sebastian's tenth birthday. Oscar was never comfortable around large crowds and preferred to look for seashells among the rocks by the ocean. Sebastian excused himself from his own party so he could accompany him. Oscar took the opportunity to find Sebastian a precious gift: a lovely pink conch shell. Sebastian was so touched by the gesture he promised to give Oscar one of the highest honors in his court when he became emperor. Of course their relationship continued to grow long after that day, and Sebastian would still have the conch shell in his possession long after the war.

Here's what I have so far of the short in prose form:

“Let the festivities begin,” Emperor John cheered. Music emulated from the musicians’ fingertips, and the nobles strode two by two onto the dance floor. Sebastian glanced through the washes of colored dresses and suits and found his little sisters Suzanna and Madeline playing with their porcelain dolls. Oscar was gazing through the window, isolated from the crowd.

“Father, can I be excused please?” Sebastian asked.

“Of course! Just don’t take too long. It’s extremely rude to abandon your guests without a good reason.”

Sebastian hopped off the oversized gilded throne and dashed to his brother.

“Hello Oscar! Why aren’t you dancing with everyone else?”

“I don’t like large crowds. They make me claustrophobic.” Oscar shifted his feet and looked out the window again, towards the sea. “I’d rather be out there.”

Please tell me what you all think. Should I finish this short story, and what improvements can I make to what I have so far?