I'm a big girl now.

Janet van Dyne as Giant Girl of Earth-20051 from Marvel comics

Janet quickly achieved high social status and used her wealth and fame to try to bring aid to those who needed it. She joined charities and did many other things to achieve this goal, but felt her calling was more along the lines of crime-fighting. Janet asked Van Dyne Industries' top scientist, Hank Pym, to make her a super hero. Pym, luckily, had been working on a device that, when worn like a harness, allowed the user to reduce their size to that of an ant. The lab was invaded by Hydra agents in exo-suits after one of Pym's inventions, to which Janet responded by demonstrating to Pym that his harness could also allow the user to grow in size as well, an ability she used to drive off the Hydra goons. Pym worked on several versions of the harness until he finally incorporated it into a form-fitting suit that Janet decided to wear as Giant-Girl.