Millie is a talented central midfielder who is a lifelong Bolton fan and season ticket holder. She began her footballing journey at Cherrybrook at the age of five and later joined a boys' team where she primarily played defence until U12s.

At that point, she signed with Liverpool FC before returning to a girls' team and eventually rejoining her old boys' team, where she started playing in midfield. After leaving the boys' team at U14s, she joined Bolton Girls at and also played for Ashton Town before making the step into first team football.