A teenager accused of plotting Mad Hatter-inspired terror in London told jurors she would have gone "straight to hell" if she had done it.
Safaa Boular, 18, allegedly chatted to her sister Rizlaine about a proposed knife attack while she was in custody for attempting to travel to Syria.
The prosecution claim they talked about an Alice in Wonderland tea party with cakes and cucumber sandwiches as a secret code.
Giving evidence at the Old Bailey, Boular said her Islamic State fiance Naweed Hussain had three times suggested she carry out an atrocity in the UK after she was prevented by police from joining him.
But Boular has said she always refused to be part of it, and they would go back to "love-dovey" talk.
Under cross-examination, she denied she was set on martyrdom after Hussain was killed in a drone attack last April.
In a conversation with an officer, posing online as Hussain's commander, Boular relayed his plan to attack the British Museum with a Tokarev (handgun) and pineapples (grenades), jurors heard.
Boular was asked why she would have told an IS commander that her "heart has been set on this for some months", if that was never her intention.
The teenager said she had "flowered it up a bit" because she was feeling sad at learning of Hussain's death in Syria.
She said: "It was just an emotional day. It was the perfect opportunity for me to express my low mood, my suicidal thoughts. I wanted to die but I did not think my life was worth living."
Prosecutor Duncan Atkinson QC said: "You have been in conversation with Mr Hussain about an attack in this country and you were reporting back to the role player, who you thought was Mr Hussain's commander, what the plan was.
"At no stage did you tell the commander that you were not committed to the plan."
Boular said: "It was my way of letting him know how I was feeling. I never really wanted to do anything.
"I never had the courage to do anything. Had I done an attack I believe I would have gone straight to hell because of my inconsistent prayers."
Boular was 16 at the time she met Hussain online, and 17 when she learned of his death in Syria.
The defence have said Hussain, in his 30s, from Coventry, had groomed her for terrorism.
Judge Mark Dennis QC asked Boular if Hussain knew her age, that she was at school and living at home with her mother.
The defendant, who believed they wed in an online Islamic marriage, said he was aware.
On why the IS fighter sent her £2,500, Boular said: "He was sending me money because as my husband it was his duty."
Judge Dennis adjourned the case until Tuesday morning when closing speeches are expected to begin.
Rizlaine Boular, 22, of Clerkenwell, central London, has admitted planning a knife attack on London and her mother Mina Dich, 44, has pleaded guilty to assisting her.
Her friend Khawla Barghouthi, 21, of north-west London, has pleaded guilty to failing to disclose information about a terrorism attack planned by Rizlaine Boular.
Safaa Boular, who lived at home with her mother in Vauxhall, south-west London, has denied two counts of preparing acts of terrorism.