However, injuries and changes in personnel since the turn of the year have seen him thrust into boss Tony Mowbray's plans.
Darren O'Dea returns from suspension and Glenn Loovens and Jos Hooiveld are battling back from injury but Thompson, 19 on Thursday, is likely to retain his place in the heart of the Parkhead defence - and he is relishing a different view of the Glasgow derby.
"I was there as a supporter as I wasn't in the squad and the atmosphere was unreal," he told the Celtic View.
"It wasn't what I expected, so I can't imagine what it will be like being on the bench or playing but hopefully I will get the chance.
"But I think that, once you get on the pitch, it will be an amazing game to play in.
"I have never played in any kind of derby before, so it will be a first for me, but something I am looking forward to.
"These are the games that everyone wants to play in. It's one of the biggest derbies in the world.
"Again, it depends on whether I am selected.
"But, if I am not in the team and on the bench, then I will be raring to get on."
While Thompson's introduction to first-team football has come sooner than expected, he is confident of standing up to his biggest test to date as Celtic try to reduce the seven-point gap Rangers enjoy over them at the top of the Scottish Premier League.
"Confidence is a big part of football and I am confident in my own ability," he said.
"The manager has told me to forget my age when I play and not let that hold me back.
"The game is all about challenges coming your way, so I will work hard and hopefully I will come through the other side.
"I hoped to play as soon as possible but I never expected to play as early as I did.
"And, after I started my first game, I didn't expect to play as frequently as I have been.
"But there have been injuries, and that is what happens in football, so I have just been ready when needed."