Jane Eyre help please

For my English A-level, we are doing text transformations, i.e. taking one text, and transforming into another genre.

I have decided to take the character Helen from Jane Eyre, and write a monologue from her point of view, as she watches Jane grow up and live.
Obviously as Helen is dead, it's as if she is speaking from heaven, like a sort of The Lovely Bones style.

I am really struggling in writing in th 19th Century style, and trying to get Helen's character across.
Also as i have a word limit, which events of Jane's life should i focus on?

Help would be really really appreciated ! :)

Thanks in advance.