Details about Cogman's very early years are somewhat scarce, but she grew up in England. Her early exposure to British culture and history likely influenced her later writing.

Specifics regarding her primary and secondary education are unavailable, but these years would have been crucial in developing her reading and writing skills. It's likely she showed an aptitude for humanities subjects during this period.

Cogman studied Hospital Pharmacy at a university, gaining an interest in the history of medicine and the influence of literary works. She also studied forensic archaeology at Bournemouth University. She spent 10 years working in the NHS after her education.