The 20-year scored on his debut for Peter Taylor's side in their recent 3-0 friendly win over Uruguay, having been selected in the 21-man squad to travel to the tournament in Turkey this summer.
Reach made 20 appearances for the Championship club last season and he says that playing first-team football has helped him to improve as a player.
"Playing for Middlesbrough certainly helped me to progress and mature on and off the pitch," he told The Northern Echo.
"Peter Taylor, the Under-20s coach, has obviously watched me play and hopefully he likes what he sees.
"I will kick-on now, hopefully have a good tournament and it will be great experience going back to Boro for pre-season."
The youngsters will face Iraq in their opening game of the tournament on June 23 and Reach says he is relishing the prospect of being involved.
"Turkey has been great so far and we're still trying to acclimatise to the conditions at the moment which isn't always easy in this heat," he said.
"I can't wait for the World Cup to start, it's my first international tournament and it's a huge honour to play for your country at any level. The experience is going to be fantastic, hopefully I get to play some football and if not I'm still going to enjoy it.
"Training has been good, we've been getting used to the conditions and the environment around us. It's always important to get a couple of weeks training under your belt and the boys are looking very sharp already."