She felt a cramp in her hands. She blinked and looked down, wondering what was going on. Her ring felt insanely tight. A second later it slid off her finger with a pop, and rolled on the classroom floor.
Madeline Zima stared wide-eyed at her hand, when the strange cramp started going through her body. Her joints shook involuntarily. Her underclothes felt strange. When the feeling passed her chest, she leaned back and pushed her arms behind her body, she couldn't help herself. The top buttons of her uniform shirt tightened, exposing oval gaps, and then a button snapped off. Another one twisted and broke away, exposing her undershirt. She gasped, and crossed her arms, hugging herself. Her desk looked lower, and most strangely, she felt she was being pushed into her chair. Nobody was noticing this yet, but they soon would. Luckily, the other buttons stayed on, but some skin could be seen. Her school uniform's jacket felt very tight around the shoulders. Then another button popped very forcefully. She felt cold air tickling her waist.
"What are you doing?"
Madeline couldn't answer, for she was almost paralyzed as her shoes constricted her feet. Then she heard creaking and felt the air on her toes as they slid out through widening gaps in the front.
Madeline was horribly confused. Her ring was now on the table as the kid to her left had put it there. Buttons were scattered about her, which left her shirt and jacket open. Under her jacket, her white undershirt seams slowly split at the top, revealing more pale skin than they were supposed to. Finally her shoes fell from her feet. At least her stockings were still where they were supposed to be, though her big toe had broken through. She shook her head and bit her lips.
Madeline stood up in a daze. She took her broken shoes and leaned down, trying to fit the pieces back onto her feet. Now the other children could see what was happening to her clear as day. There were loud shrieks and screams, and she heard stumbling footsteps around her. She hardly cared as her legs lengthened. The door slammed open and shut several times.
Next she tried to put on her gym shoes. They came apart too, her toes breaking through the front before she could even push her heels inside.
She frowned, and tried pushing the ring back onto her finger. She could hardly get it halfway up, unlike before when it had been at the base. She could feel the ring tighten again as her finger got longer. Her jacket couldn't close all the way anymore either... No, it was impossible.
She quickly walked to the door of the empty classroom to leave, when she noticed other differences. The shelves were shorter. She usually was as tall as the shelves, but she was now taller than them.
She knew what was happening of course, she wasn't stupid. She was growing up, or at least her body was.
Carrying pieces of her shoes and her ring, she quickly exited the room.
She almost forgot about her school uniform until the jacket sleeves separated at the shoulder seams and slowly crawled down her widening arms. They tore at the elbows when she bent her arms. Her skirt tore more with each step. She found that she couldn't slip it down her bouncing hips without ripping the plaid fabric. Instead, she tugged at a loose edge, and a piece fell to the floor.
She couldn't see their form through her overstretched shirt, but she was definitely getting breasts. She decided she wouldn't cry no matter what.

Madeline crossed her legs and tried to unbuckle her belt but it was pinched tightly around her toned stomach. Unexpectedly, her underwear came apart and fell between her legs. She licked her lips. Even they felt bigger.
She looked down, seeing the fabric strain impossibly tight as her body left her clothes behind. The remaining wrinkles smoothed out, becoming flat. Pieces of her ripped skirt slid down her widening legs. The stockings tore completely off her feet and knees. Crusts of purple nail polish still stuck to her longer toenails. Her huge breasts broke free as she raised her arms to feel her hair. It felt thicker and heavier now, even though she was so much stronger. What would her parents say?
She could feel the last remnants of her skirt caught around her waist, where they bunched around her straining belt. They got tighter with each breath as she finished the age shift. She pulled a tattered edge back down to cover an embarrassing glimpse of pubic hair. Her nipples stuck out like sore thumbs. The human body was a wonderful thing but she didn't want to put on a show for everyone. Her white undershirt underneath her school uniform had torn in half along her front and back, as had the back of her jacket with a horrible rip earlier.
She stood up, and stretched out like she was yawning. The last shreds of fabric fell off her perfect body, and she was completely naked. She had to be 5'8" now, and double her original age. Basically she was a woman, and a knockout she could tell. She had grown a foot in minutes, ripping through all her clothes and destroying her shoes.

There had been a time when birthdays had been a cause for celebration, and a day in which she might expect a new doll, or a new dress. Though she had long since outgrown her doll, she had also outgrown her clothing, and they fitted tightly. She wouldn't have minded a new dress, or maybe even only one hair ribbon.

... her body tingles and changes.
She changes. Her child frame shifts, losing the form of childish youth and taking on the curves of majority.....of womanhood. She gains mass as her frame turns more mature, becoming stronger, as her stature suggests. Her hips widen and she finds herself tearing her clothes in a manner that has become too familiar since the onset of puberty. Her hair shifts and changes, grows.