The Swansea City midfielder, on loan at Blackburn Rovers, is enjoying his first call-up to Gareth Southgate’s squad after captaining the U20s.
But while the Young Lions’ 3-1 home win with Switzerland back in November was easily the most fiercely contested of their Euro 2017 qualification campaign – Grimes is unlikely to let the atmosphere in Thun get to him.
Switzerland v England
UEFA European U21s Championship
Qualifying Group 9
Arena Thun, Switzerland
6pm (GMT) 27 March 2016
Live on BT Sport 1
“You always want to play in front of a crowd in front of noisy, great fans but it's something that you can't let take control of you,” said the 20-year-old.
“I'm not one to get influenced by a crowd or let my emotions get controlled by fans. Some people let it get control of themselves and put in a daft tackle but it's never really affected me.
“You just have to trust in yourself and not let things manipulate what you are trying to do.
“If you're given a task on a Saturday to go and just mark one player you can't let people distract you from the job.
“You just need to keep your head focused and not let anyone get in amongst you.”
Watch highlights of England U21s' home leg win over Switzerland
Grimes’s calmness will be encouraging to Southgate as his squad look to extend their lead at the top of Group 9.
England are three points ahead of Norway and Switzerland at the halfway stage and a victory in front of the BT Sport 1 cameras on Saturday would be a giant step towards booking a place in Poland in 2017.
But it is business as usual for Grimes, who immediately felt comfortable after stepping up an age group.
“There are a lot of friendly and familiar faces from previous camps although a few new ones too,” he said.
“Like every time I come away with England everyone is so welcoming - it makes it easy to settle in and get straight on with training.
“I just think it is run by good people and we are very selective of who we bring. Everyone gets along so well.
“And when you are away with England you have to represent your country so if you're doing things that don't sit well with the coaches and staff then you won't get picked.”
Grimes is enjoying an extended spell of first-team football while on loan at Blackburn after finding games at Swansea hard to come by.
“I was struggling a bit at Swansea in terms of games and getting a run to find my top form which was frustrating,” he said.
“But then going to Blackburn and getting a run of games in the team and training all week and thinking 'I'm playing on Saturday' - that's what you need as a player and it has resulted in me being called up here.”
He admits that the move from League Two Exeter City – his hometown club – to the Premier League was an eye-opener, but the Championship is suiting him well.
“It's a bit different to playing in the Premier League but it's a different challenge and one I'm relishing,” he said.
“In the Championship there is a lot of top quality that is looking to get into the Premier League. It’s a difficult league and the players are very hungry in that they all want to be the next step up.”
Grimes comes across as a player with a good perspective on life. There won’t be too many footballers with a take on ultimate frisbee but the Devonian smiles when asked about his old hobby.
“I played it when I was at school, from the age of 11 until I was 15. One of my mates just said 'come along on a Friday, you'll love it' and so I went along and I did,” he said.
“Don't let the highs get too high and the lows get too low”
“It was a good escape for me. Very good for fitness and footwork and I really enjoyed.
“At a young age it was good to have a bit of an escape from football. Sometimes, especially with younger players in the academy it can be a bit too full-on and they need to do something and get their mind off playing.
“It’s good to remember - don't let the highs get too high and the lows too low.”
He added: “I'm quite keen on golf now so I'll have a round and that's four hours that takes my mind off football.
“I was fairly good when I was younger but I don't play enough now. I probably 18, just in the summer, but you need to play consistently to get better.”
Grimes will admit the same is true of playing football, and with Blackburn and now England U21s, he is hoping to do exactly that.