But just over two years on from her switch from Portsmouth Women, the Watford-born winger celebrated her 50th appearance in black and white in Sunday's 1-1 draw with Ipswich Town Women - and marked the occasion with a goal.
While Newcastle's number 26 experienced a rough start to life on the pitch, tasting defeat at home to Nottingham Forest Women on her debut, there have been several high points since.
Lumsden told newcastleunited.com: "When I joined the club, I didn't know I'd end up making 50 appearances, but it's been such a great experience for me and hopefully, I can go on to make 50 more.
"When I joined, the club had similar ambitions to mine, and I know it sounds cliché, but I want to reach the top of my game - and I don't think there's anywhere better than here.
"Everyone, especially the fans, have been so supportive since I joined the club. I've grown into the culture of Newcastle, the club, and Newcastle, the city; and I can't truly describe just how much I love Newcastle, but I'd confidently say I'm a fan for life."
Despite being in Newcastle for just over two years, the England youth international has written her name into the club's history books, become an adopted Geordie and already hopes to stay in the area post-playing career.
Three goals in 11 appearances in the second half of the 2023/24 season helped United earn promotion to WSL2 for the first time with a 10-0 win over Huddersfield Town Women securing the title in her first campaign.
"If I could do it all over again, I would, without hesitation," Lumsden said. "It was such a fantastic day for the club and all of us as players.
"From the minute we got to the ground, you could feel the atmosphere was different, and then seeing how full the stadium was, it was an amazing moment.
"Then that feeling of lifting the trophy, it's right at the very top of my career, that's for sure."
Another highlight came in October 2024, when she scored twice in a 2-1 win over Sunderland Women at the Stadium of Light.
"There aren't many days that go by when I don't think about it," United's 'Mackem Slayer' admitted with a wide grin on her face.
"I've said it before, but I honestly didn't realise how big a deal it was for me to have scored and beaten Sunderland. It wasn't until I got back into the changing room and my phone wouldn't stop and people just kept talking about what I'd done.
"There have been some really special times with this club and my teammates, but those goals and that day are something that will stick with me forever, not just while I'm here, but for long after as well."
For a player who spoke openly in 2024 about her goals and dreams of playing in the WSL (Women's Super League), missing out on another promotion last season was tough to swallow, despite Newcastle being newcomer to the league.
But being happy off the pitch is the secret to Lumsden's displays in black and white, and she signed a new contract in March 2025.
"No, not at all!", the 26-year-old emphatically said when asked if she debated not extending her stay with United.
"I was, and still am, very happy at the football club. So it was a no-brainer for me when talk of a new contract was mentioned, and it didn't take long for me to say yes and extend my time here. I feel really settled here and call Newcastle my home.
"Everyone is so friendly here - people walk past you on the street and say hello, it's such a calm way of life, which is perfect for me, and my boyfriend lives here, which definitely helps.
"I'm not naïve to think everything is going to go to plan here, but I'm an ambitious player at an ambitious club, so I just want to stay here as long as possible and be a part of more memories and getting this team into the WSL."
