First day

This blog post is a writing exercise from writers.stackexchange.com. Visit the Writers chat room every Tuesday for new writing exercises. This week's exercise: A microfiction (no more than 600 words) story with a first-line prompt of "She did her best, but she was young."
She did her best, but she was young. She sat in her chair, her legs wrapped around its, hunched over the paper. Her fingers gripped the pencil tightly as she concentrated on her work. Meticulous stroke after meticulous stroke.

At one point someone with a ball crashed into her, prompting her to put down her pencil and exclaim “Be careful! I’m writing here!” before turning back to her work. She gave an exasperated sigh as she erased the errant stroke caused by the juxtaposition of her elbow and a kindergartener.

Unmindful of the clock on the wall, she toiled away until her paper was filled to her satisfaction. Smiling, she put it aside, only to see that it was time to leave. She jumped up to go change her shoes and grab her coat, snagging her paper almost as an afterthought as she ran towards the door.

“Daddy, Daddy, look what I wrote!” she beamed as only a four-year-old can.

“Let’s see, honey!” he said, as he picked up the paper and examined the huge letters scrawled across the page

DEARDADDY I
MISS MOMmy
wHen CAN WE
GO SEE HER

“Did I write it good?” she asked, hopping from one foot to another.

“You did, honey,” he said, a tear forming in his eye.

“Did I make any mistakes?” she asked excitedly.

“You spelled every word right, but some of your letters need practice,” he said gently. “Mommy would have been proud of you,” he added.

She took his hand, and they left the classroom to go home.