Norway international midfielder Hegerberg, 23, made her Blues debut in Wednesday's Women's Super League One goalless draw against Arsenal.
"At first I wasn't that interested," Hergerberg told BBC WM.
"But after talking to both David and Marcus and hearing their plans, they caught me."
Hegerberg became Birmingham's fourth foreign signing since April when she joined from Swedish side Kopparbergs/Gothenburg following the departures of Jo Potter, Jade Moore and Remi Allen.
With the club keen to return to the level that saw them reach the Champions League semi-finals two years ago, Hegerberg is looking forward to helping realise that ambition.
"To be a part of the football development here in England - which is fantastic - is something I want to contribute to," she said.
"The Champions League is something I want to be part of and hopefully we'll make it some day.
"It's been amazing so far - I've come to a really good club."
Blues' draw with the Gunners kept them third in the WSL 1 table, six points behind Chelsea Ladies in second place and eight adrift of leaders Manchester City.
Andrine Hegerberg says Birmingham City Ladies' boss Paul Parker and football consultant Marcus Bignot changed her mind about playing in England.