Sandcastles and Swings

Jenny smiled as she reached the park and let the soft sand slip between her toes. It was her birthday today, and she'd always enjoyed feeling the cool air lightly brush her skin and tangle her hair as she went down the slide. She looked around and saw kids with their parents and vaguely wondered where her own parents were. Jenny ran for the swing and began thrusting her legs forward and back. She knew that starting the swing up was always a difficult task and that her hands may hurt a little from pushing and pulling, and yet she kept at it. Pull, push, pull, push, pull, push... Jenny gained speed as she traveled higher and higher, her hair flying in all directions, her heart racing. And as she reached the highest point of her swing, she spotted her parents and yelled out: 

"Mommy, mommy! Look! I still got it, I still got it!" 
Her mother looked at her, mortification grazing her features. 
"Jennifer, stop swinging! Stop swinging!" 
Jenny let her legs go slack as she surely started swinging less and less. And as she finally stopped swinging altogether, Jenny got up feeling slightly dizzy and joined her parents near the park bench. 

"Jennifer, I know it's your birthday. But don't you think you're getting a little too old for this?"
Jenny laughed. "I'm still young, mom."
"You're thirty. You're hardly young anymore, sweetheart. Just go put your shoes back on, alright?"
Realization hit her as she slowly slid her shoes back on her feet. Her mother was right. Jennifer frowned as she looked over her shoulder at all the children building sandcastles and balancing themselves on the monkey bars. Sighing, she turned back around and vaguely felt her aching legs moving as she walked far away from the tiny playground.