The former England youth international was part of the Crystal Palace Women's team which lifted the Women's Championship title last season but was left blown away as she stepped out at Hayes Lane as a second-half substitute on the opening weekend of the current campaign.
The loanee was stunned by how many Magpies fans made the long journey down to the capital almost two weeks ago, but has quickly understood what the club means to the supporters, who she believes are among the best in the country.
"I think this is one of the biggest fanbases in women's football across England," Sibley told newcastleunited.com ahead of this weekend's visit of Sheffield United Women.
"You don't get crowds like this on a regular basis in women's football, so for us to be able to play in front of thousands of fans at Kingston Park keeps pushing us on to reward our fans.
"When I walked out onto the pitch against London City I could just see a sea of black and white shirts and I have to admit, it gave me goosebumps just sitting on the bench."
While Sibley was busy winning the league with Palace last term, a crowd of 22,307 at St. James' Park for February's FA Women's National League Cup victory over Portsmouth Women caught her eye.
United have become well-known for their loyal support both home and away, and Uxbridge-born Sibley is keen to reward the Geordies for the love they've already shown her.
"I've heard a lot of great things about playing at Kingston Park and the girls have been telling me about it ever since I joined," she explained.
"Last year I saw all over social media the number of fans who come to the games. It will be so special having all the fans cheering us on.
"It's crazy how much women's football is continuing to grow. Being able to walk out in front of thousands of fans in black and white shirts is pretty surreal and always puts a big fat smile on my face."
Sibley was pleased to pick up a hard-fought point on the opening day of the season in Bromley, and she's expecting another tough test this weekend.
Sheffield United Women remain winless this season but are yet to lose by more than a one-goal margin, so Sibley and her team-mates are under no illusions as to the task ahead.
"They look like a good side," Sibley added. "It'll be a competitive game because Sheffield United are not always the easiest team to play against.
"Training has been brilliant since the London City game. There's still a lot of work to be done but we're putting stepping stones in place for each match and continuing to learn.
"It's just so exciting to see us continue to improve and get better with every single training session."
Tickets for Sunday's game against Sheffield United Women are on sale here. Season tickets are on sale from book.newcastleunited.com.
