Kelly, 26, previously played for Sunderland Women in the Women's Championship, but insists that making the move to Becky Langley's side, in the FA Women's National League Northern Premier Division, is not a step down.
"(It feels) amazing," she told nufc.co.uk when asked about her emotions on joining the club.
"I don't think there could be a more exciting time to sign for Newcastle. I feel like with the momentum and the success of last season, it's going ahead in the right direction.
"With the professional status, it makes it even more exciting. I am very grateful for the opportunity and looking forward to getting started.
"I've had experience in the top three, four leagues. Every girl wants to be playing in the WSL (Women's Super League).
"It's where the highest standard is at now and it's where we are aspiring to get Newcastle to."
Kelly also plied her trade for Middlesbrough Women in the past, where she lined up alongside Newcastle Women boss Becky Langley, and the midfielder is thrilled to reunite with her former team-mate.
"All the girls and all the staff have been really welcoming," she said. "Knowing Becky and having played football with Becky when I was at Middlesbrough, it is good to come into an environment like this.
"I am looking forward to a new challenge (and) a new environment. I feel like I'm playing with my friends again."
Following the announcement of Newcastle Women's fixture against West Bromwich Albion Women at St. James' Park on Saturday, 5th August as part of the inaugural Sela Cup, presented by VisitMalta, Kelly says she cannot wait to have the opportunity to play at the 'cathedral on the hill'.
"That was probably one of the main factors that drew me to Newcastle - the fanbase and the support they are getting and the backing from the men's side to allow the women's to play at St. James'," she continued.
"I feel like this is a thing that most female and male teams should be striving to do now. I think that Newcastle have promoted that well. The fanbase and the support we are getting is amazing.
"To have the chance to play in front of a crowd like that is something that would just be an amazing experience altogether."
See Emma Kelly in action when Newcastle United Women play West Bromwich Albion Women at St. James' Park on Saturday, 5th August as part of the two-day Sela Cup, presented by VisitMalta. Buy tickets here.
