I want to dress up as her for Halloween at school, cause our highschool always has dress-up day competition but I'm just not sure if anyone will know who it is, teachers or students. haha
Pippy Longstocking is a character who has appeared in books; comic magazines, films, and tv series.
She is typically portrayed as a scruffy primary school aged child (about grade 4 or 5) and is, as her name suggests, invariably wearing knee length or above the knee socks and they are often mismatched. She is usually depicted with red/ginger hair, braided to each side of her head and tied with ribbons.
A Google Images search will yield a plethora of pictures to give you ideas for a suitable costume and make-up:
I think it is a wonderful idea to dress up as her for Halloween, and I recommend you read a book about her. Some are available as .pdf downloads e.g. at http://english4success.ru/Upload/books/72.pdf
It should not come as a surprise to learn that older girls often attend fancy dress events as a somewhat older Pippy, dressed in an erotically provocative manner, somewhat in the manner of a St Trinians sixth former.
What shall we do today, what shall we do today? What shall we do today, what shall we dooooo.
Not many younger people will know.