BBC Middle East correspondent Quentin Sommerville tweeted: "IS supporter Shamima Begum admits to BBC News she was a poster girl for IS recruitment, apologises to Britain for joining IS and says she is ready to face prison if she’s allowed to return."
Ms Begum added in the interview: "I actually do support some British values and I am willing to go back to the UK and settle back again and rehabilitate and that stuff.
She added: "The poster girl thing was not my choice."
Begum also discussed watching propaganda videos put out by the terror group, along with al-Qaeda-linked groups.
Worryingly, the teen "still believes IS propaganda", says the BBC correspondent, adding, "when I asked her about the enslavement, murder and rape of Yazidi women by IS, she said 'Shia do the same in Iraq.
"She had little to offer in way of apology to the millions of Iraquis and Syrians whose lives were destroyed by IS."
During the wide-ranging interview, Begum left momentarily to “feed her two day old baby boy”, tweets Sommerville.
He added: “He is under her abbaya [full-length outer garment]. She says she hopes her family will gain custody of him if she is imprisoned.”
The claims come just 24 hours after the Brit indicated she was little more than a "housewife" during her time in battle-hardened Syria.