Who is Sophie in howl's moving castle?

sophie is the oldest of 3 sisters who run a hat shop she is described as the smartest of the 3 and uses all of her time to make hats while her sisters have fun outside (sophie and her sisters are not little kids i'd say 19-21) sophie goes out for a walk then comes to the hat shop to lock the doors she locks them and turns around walking away when some one comes in the locked door she has no idea who she is so she says a little rudely to leave the woman said u dont know who i am do u sophie contorted her face the screams the witch of the waste the witch gives sophie a horible curse that makes her 90 err 93 idk some wher 90 and 93 years old this is thaking to long so sophie runs away finds howl takes calcifer out of the castel and crashes bla blah whach the movie by hayao miyazaki