While an interesting story, Charlotte Bronte before Jane Eyre felt like something was missing. It is more of a few panels/pages hitting highlights of Bronte’s life 
than a full-on biography. In other words, if you need a biography to do a paper on, this is something fun to help you summarize, but one should not to take it as your only source. Glynnis Fawkes is obvious a fan of Jane Eyre and Bronte, but you do not have to be to appreciate what happens to Charlotte. Introductions and afterwards help summarize the book.
The black and white illustrations can make it hard to follow/see who is speaking at times. The colored cover would have been nice in the entire graphic novel. Or even a few pages. I am guessing this choice of black and what was chosen over color illustrations deliberately as color can be expensive to print. However, the art has Charlotte and her family’s life unfolding as you read along. We see some of the issues faced (poverty, illness, death of her parents and sisters) and how she overcame them. Seeing the personalities of the sisters, they would have fit right today. Women of their time and ahead of it at the same time at the same time.
If you are a fan of Jane Eyre, you might like to see an interpretation of how it came to be. If you enjoy the history of women’s literature or literature in general, you also might enjoy this. But as mentioned, you do not have to be a fan to enjoy this non-fiction story written in a fiction tone. Teens to adults can read. Due to the pace a strong 12 to adult would be the best audience.