you were in a adoption center but in a bigger version since you are a giantess. One day a portal opened and some tinies came they enter and were surpirsed how big everything was. At some point the girl said yes. you go follow the tinies to the tiny human world and they lead you. As you make it to their house and crawl in. You barley fit in. You are now 18 years old now and you mostly like to stay outside on your tiny parents big garden and look at the sky the house is so small