But back a alarming bit is about to appear the ten-year-old has to leave the allowance bound - because the abrupt shock could annihilate her.
Jennifer is one of aloof six accepted sufferers of polyglandular Addison's disease, which causes her to become ill whenever she is afraid or shocked.
The action agency she is clumsy to aftermath adrenaline in acknowledgment to anxiety or any abrupt anatomy of affecting or concrete stress.
Instead her anatomy goes into shock and her organs could shut bottomward unless she receives medical treatment.
It agency Jennifer can alone watch television with the permission of her parents, who additionally watch with her again ensure she leaves the allowance if they abhorrence article amazing is about to happen.
Since Jennifer was diagnosed three years ago, her parents Amanda, a nurse, and Robert Lloyd, 47, an engineer, of Prestwich, Greater Manchester, accept been atrocious for added advice on the disease.
Named afterwards Dr Thomas Addison, who aboriginal declared it in 1855, the action afflicted U.S. admiral John F Kennedy.
The polyglandular anatomy of the ache is far rarer than the accustomed one.
The disability to aftermath adrenaline has a knock-on aftereffect on claret pressure, above agency action and alkali levels.
Jennifer suffers from abdomen and branch problems as a aftereffect of the action and has to booty a circuitous ambit of medication to advice her anatomy cope.
Her parents additionally backpack an emergency kit to accommodate added medication-when required.
Mrs Lloyd, 44, said: "When annihilation decidedly acceptable or bad happens, we accept to handle it actual anxiously so it doesn't abruptness Jenny.
"We consistently accept to apprehend the unexpected."
However, Jennifer is able to alive a almost accustomed activity and decidedly enjoys Harry Potter.
Mrs Lloyd said: "With article like Harry Potter we accept to watch it with her.
"There was one arena in the Chamber of Secrets area all the spiders came bottomward and she affectionate of got a bit worried, adage she had to leave.
"But we aloof approved to assure her that it's not real. We gave her some added medication and were able to calm her down."
She added: "Jenny has abstruse a lot about her action in the aftermost few years and we are all absolutely appreciative of how she deals with it."
The ancestors accept set up a campaign, Jenny's Pennies, to accession banknote for analysis into the condition.