Kelly feared he had boarded a sinking ship when he visited the Madejski Stadium, but became convinced his new team are capable of avoiding the drop after watching them mount a stunning comeback against Albion.
Kelly became Reading's third signing of the January window on Saturday when he left Fulham and signed a two-and-a-half-year deal with the Royals.
Reading invited the Republic of Ireland full-back to watch their game against West Brom that afternoon and, for 82 minutes, Kelly must have been thinking he had made the wrong decision.
Brian McDermott's side were 2-0 down and, with QPR having drawn with Tottenham earlier, were bottom of the Barclays Premier League, but late strikes from Jimmy Kebe, Adam Le Fondre and Pavel Pogrebnyak handed the club their most thrilling win of the season.
Given they are three points from safety with 16 games to go, Reading are still among the favourites for relegation, but Kelly thinks the shock comeback will give his new employers the drive they need to climb out of the relegation zone for good.
"After watching the game at the start it was looking a bit grim," Kelly said. "But to be able to come back, hold on, and show that kind of character and fight is exactly what you need to stay in the Premier League.
"That win has put us closer to the other teams. You look at the table and think it's not impossible.
"I am confident we can stay up. After coming here and meeting everyone affiliated with the club you realise everyone is determined to stay in the league. The determination is unbelievable.
"I want to play in the Premier League and I feel confident we are capable of doing that."
After spending most of his first two years at Fulham on the bench, Kelly finally secured a place in the starting XI last term, but the arrival of Sascha Riether on loan from Cologne restricted him to just one start this year.
When Kelly decided to move on, McDermott was the first man in the queue. The 51-year-old had met Kelly at the wedding of former Reading man Kevin Doyle two years ago and the two immediately struck up a close bond.
"When I met him I took an instant like to him," Kelly said of McDermott.
"I am quite close to Kevin and he is close to Brian so we bumped into each other that night and had a good long conversation about football.
"He was friendly, we got on quite well and I bumped in to him a couple of months back when Reading were flying over to Dublin to play against Bray.
"As soon as he came in for me this month and we sat down and had a chat it was easy for me to make the decision to come here."
Having played with Nicky Shorey, Pogrebnyak, Alex Pearce, Ian Harte and Jay Tabb before, Kelly has settled in easily during training at the club's Hogwood base this week and is keen to be thrown straight into the team for Saturday's trip to fellow strugglers Newcastle.
"Sometimes people can find moving awkward and difficult, but I've been here two days and it feels more like two months," the 29-year-old said. "It's amazing. I didn't think I would settle in that quick. Everyone has been so welcoming.
"They've been brilliant so I've found it very easy so far and hopefully that will show this weekend."