Bigger Please?

A girl character from a book breaks the 4th wall & asks the author to make her a giantess.

Betty was a 5ft tall pretty girl that longed for bigger things...

"Hey author!"
"Yes Betty?"
"Speaking of bigger things, I want to be bigger!"
"Oh, how much?"
"How about big enough to use my house as a chair?"
"Alright, just for you Betty."

Betty was inside her bedroom when she felt a power come into her body. She felt pleasantly warm and discovered that her bed felt a little cramped. She was growing! No longer just 5ft tall, she continued to grow until she was 10ft tall, then 15ft, then 20ft. She was so big now that her massive frame ripped through the walls and ceiling causing her house to collapse round her.

"Hey author, can you make me even bigger? Oh, and while your at it, make my chest bigger. The bigger the better."
"If that's what you want Betty."

Betty hadn't stopped growing for a long shot. She continued to grow higher and higher, but what was even more surprising us that her chest expanded ever more swiftly outward, increasing in size even faster than the rest of her. Soon her chest was as big as the rest of her and the rest of her towered over the small city she called home.

"Hey author!"
*Sigh* "Yes Betty?"
"I want to dominate the planet!"
"Betty, I'm done with this, be thankful you get to be this big."
"Oh, pooh. You're no fun."

Betty spends the rest of the story rampaging the town, stepping on cars to squash them, uprooting trees, and tipping over skyscrapers when her chest gets in the way.