Jess's mind was reeling with all the things she could try as a girl now that she'd turned into a female version of her younger self, but Ashley's question reminded her that her sister hadn't gotten to use the program yet. "Wait, Ash! What about you? What do you want to change about yourself?"
"Oh! Well, I mean... I guess you're change has got me thinking..." Ashley had turned away from Jess, but the younger girl could tell her sister was blushing, maybe a bit embarrassed by her idea?
"Sis," Jess spun from the mirror, ready to tell her big sister not to be ashamed about anything, but before she could, Ashley blurted it out.
"I want to try being your older brother!" Ashley was still flushed, but continued "I, I mean, not just change gender, since I am older than you now... I'd like to be older than this."
Jess wasn't shocked, and wasn't really sure why Ashley had been so embarrassed about her idea. "That's cool, Ash! I mean, there's no reason to be so weirded out about it - look what I just did with the machine!"
"I know, I guess... I guess I just didn't quite believe it could be true until it worked on you and... well I've actually dreamed of this for sorta a long time." Ashley flopped into the computer chair, her blush finally beginning to fade.
Jess grinned. "Well go for it! Let's make that fantasy a reality, at least for the weekend!"
Ashley returned her little sister's smile and spun the chair to face the computer, clicking to pull up her profile. She quickly switched her gender from female to male, and Jess watched over her shoulder as she clicked the 'up' arrow, increasing her age from 10 to ... 24 years old!
"Wow, okay. You really wanted to go for it." Jess teased. "But why do you want to be so... old?"
Ashley huffed "Twenty-four is not THAT old, silly! I guess I've just always wondered what it would be like to be 'grown up' and not a kid anymore. It seems like a safe age to test the waters a bit, don't you think? It's not like I'm going to be as old as mom and dad - they're in their THIRTIES!" the sisters both laughed at the thought of being that 'ancient.'
"You do you, sis." Jess turned and went to hop up on the bed, getting comfortable to watch Ashley's imminent changes.
"Alright, I think I've get everything. I made sure my clothes will change with me but our awarenesses will remain the same, and I set the time-limit to change be back on Sunday... unless we edit it between now and then." Ashley pushed back from the desk and went to stand in front of the mirror, taking in her 10-year-old body one last time before reaching over to press the button that would initialize the changes. "Here goes nothing!"
Jess watched Ashley shiver as the transformation began; she was excited her sister had been so into the idea of experimenting with the program! They were going to have so much FUN this weekend!
Ashley was trembling slightly, but surprisingly her nerves seem to have disappeared. She couldn't believe her longtime wish was about to be a reality, but her body had relaxed, as if ready for it's metamorphosis. Taking her eyes off her reflection, she felt slightly dizzy and realized she'd been growing taller incrementally over the first few seconds. Goosebumps raised on her arms and legs as her fine body hair thickened and darkened, tingling in her armpits and groin. "Ohh geeze, this is so strange!" she whispered.
"Just wait for the internal rearrangements!" Jess squealed, amazed at how much taller her sister was becoming. Her head was nearing the top of the full-length mirror, so she had to be pushing 6' already!
Holding her hands out in front of her, Ash watched as her fingers thickened and lengthened, loosing their childish smoothness as they became more weathered and masculine. Her arms too were thickening, muscle building in her forearms and bulking up her biceps and shoulders, which had broadened considerably! Her, breasts, which had only just begun to bud at 10 years old, were actually becoming plumper as her pectoral muscles reshaped her chest. A churning in her abdomen had her folding forwards slightly, knowing that her organs were reforming to match her changing gender. She felt a heat in her groin, the elastic of her panties stretching and sliding down to reform into boxer briefs beneath her pant just as something, no, someTHINGS slid from her crotch, a sac forming and filling, cradled in her underwear even as her new penis pushed out against her zipper.
"Oh jesus this is ... this is so ... " Ash couldn't finish the sentence, his blush returning as he just barely remembered Jess sitting on the bed nearby.
Jess was smirking though. "I WAS a 16 year old boy earlier, Ash. I, uh, think I might know what you're going through!" She hopped to the floor, quickly heading for the door. "How about I let you finish up the changes alone, huh? I'll... just go hang out in your room for a bit."