But slotting in for the injured Gordon D'Arcy two Saturdays ago, the Coleraine youngster looked the part in a 10-12-13 unit with Ronan O'Gara and Brian O'Driscoll.
Irrespective of the number on his back, he is evidently happy to continue his international development alongside two of Ireland's most influential players.
"Whenever you're playing somewhere different, and it's not that different I suppose, it's only one channel in from Ulster, but there is no better man to be alongside you than Brian," Trimble admitted.
"He's an absolute leader. He takes over whenever we've got the ball. He calls the shots and you just follow him. He's comfortable enough to say 'give me the ball and follow me'.
"That's great because it takes a lot of pressure off. And with Ronan the other side of me, I wouldn't say I had an armchair ride or anything against France, but it did make things a lot easier.
"They know that it's a little bit new to me, playing at 12, so they were very supportive.
"It's also that it's really, really encouraging for me to know that they're putting a bit of faith in me, that they're putting the ball in my hand and letting me go."
Switching positions at Test match level is particularly difficult but a frank Trimble does not mind as 'you have to keep learning new stuff.'
"In the last couple of years, I have been chopped and changed a little bit - left wing, right wing and both centre slots.
"But it's something I'm starting to get used to now. It's really only for first phase and defensive positions that you have to stand in a certain position.
"When you get into phase play, everybody ends up all over the place anyway. You get wings popping up at first receiver and so on, so it's not as daunting a task as it would seem," said the 23-year-old.
Reflecting back on the loss to France, Trimble enjoyed the experience of taking on the defending Six Nations champions in their own backyard but it was a strength-sapping performance.
"I felt like I never stopped working for the whole game. It was probably the hardest I've worked in a long time, simply because there was so much to do.
"The French play with such width and intensity, with guys coming onto the ball from every angle, that there's an awful lot of tackles to be made.
"In the 12 channel, there's a lot more happening too. Then, when you get the ball in that channel, there's a lot more responsibility, a lot more trucking it up.
"I was pleased with my work-rate and the amount of tackles I made. There were one or two mistakes, a few poor passes and so on, but I'll just keep working on those things."
Trimble was greatly encouraged by Ireland's second half comeback in Paris and feels the team can hit top form in their remaining games.
"People talk about the last half hour (against France) but the whole way through the game we posed a massive threat. We put some really good phases together and tested them in a lot of key areas in the pitch," said the Ballymena clubman.
"We just coughed up the ball too much at the wrong time. And whenever we did that, they capitalised and scored tries.
"It was really, really gutting to see how easy it was for them to score tries and how much we had to work for them.
"But it's really encouraging for us to see that we're getting back to our best.
"We showed glimpses of it against Italy and a lot more against France. Hopefully we can bring that through for the rest of the tournament and really put in some big performances."
Part of the Ireland side that lost to Scotland in a World Cup warm-up game last August, Trimble will be doing his utmost to prevent the Scots from securing what would be a surprise win at Croke Park.
"People are going to say that we're the favourites for Saturday's game. They can say that if they want and there's nothing we can do about it.
"But the way the Six Nations is going, there's surprises every weekend. So, as a result of that, there's no real favourites.
"Besides, in the last six months, we've shown how good we can be and also how bad we can be as well.
"If we can produce a good performance, we can be a massive threat no matter who we're playing against. But if we don't perform, anyone can beat us," he insisted.