Hmmm, Emily (Jackling) is aged 45 in 1851, putting her a bit younger than Elizabeth.
Maybe this 1871 census is more accurate?:
https://www.ancestry.co.uk/discovery...ew/896503:7619
The two sisters together, Emily 65 and Elizabeth 63 which fits the order on JB's will and makes Elizabeth born in 1808ish as you originally stated in the opening post.