The 25-year-old is competing in the final of the prestigious competition in Derby on Saturday.
Stephenson, from Border City Amateur Boxing Club, will take on Amelia Barker from Eltham & District Boxing Club in London in the female senior elite under-65kg final.
The Cumbrian earned her place in the final with an impressive display in last Sunday’s semi-final.
She got the better of top seed Zaynah Casserly, from Aston Boxing Club, with an outstanding performance at Rotherham’s Magna Centre.
Brodie, 25, is in Saturday’s female senior elite under-65 national final (Image: Border City ABC)
“Brodie boxed a punch-perfect contest to come away with a unanimous win,” said Border City ABC coach Ian Archibald.
Stephenson now faces Barker for the right to become England’s number one – while the Carlisle boxer is also on the radar of the Great Britain set-up.
Her progress to the final has earned her an invitation to the GB Boxing headquarters in Sheffield for assessment in May.