After her release from Hibs, she went on trial at Hearts and impressed head coach Eva Olid enough to cross the city divide.
Rennie celebrated her 19th birthday the same week and made a goalscoring debut as a sub against her old team at Tynecastle a few days after that.
“It’s been amazing at Hearts,” she said. “We’re training during the day. We’re doing gym sessions, extra sessions. It’s incredible how well the club is set up now. It’s really good. I’m really enjoying it.
“We’ll still be looking to keep the fitness levels up during this break, so we can try to hit the ground running for the rest of the season.
“We’re trying to get higher up the table. With all the extra training and gym work, that’s definitely a goal for the club.”
Rennie has SPWL1 experience already, having come through the ranks at Celtic before moving last season to Forfar Farmington, where she linked up with current Hearts teammate Aimee Anderson.
Her performances drew the attention of Hibs, and she joined in the summer but was released in October due to lack of game time.
However, Rennie has swapped green for maroon as Hearts push towards full-time professionalism.
Her timing couldn’t be better and a goal in the derby in front of more than 3,500 fans at Tynecastle got her off to a flyer.
“I was just thinking about trying to get the ball in the back of the net,” she recalled. “That’s all I was really thinking about. It’s great to finally get in the team and especially to score.”
The opportunity to play and score at Tynecastle Park is not something she takes for granted, and Rennie is hungry for more.
“It’s great for women’s football,” she added. “The older players in the league, some of them didn’t experience playing in stadiums like that. So it’s get to experience that as a young player coming through. It’s brilliant.”