United announced in January that an agreement had been reached for them to sign Zaha from Crystal Palace, where the winger is remaining for the rest of the season before linking up with the Red Devils in July.
On Tuesday, Zaha was handed a one-match suspension by the Football Association for making an offensive gesture towards Leeds fans while playing for Palace during a 2-2 draw between the two Championship sides at Selhurst Park on March 9.
The 20-year-old later apologised for his actions on Twitter.
Speaking about Zaha - who has six England Under-21 caps and made his senior international debut in November - Pearce said: "He is still one of the younger boys here, he has just had a big-money move to Manchester United, with all that brings, and he has gone back to Palace on loan. A lot has happened to Wilf.
"To be fair, I am quite delighted with how he has come in and been part of the squad.
"He seems really happy around the group and I think he is progressing just nicely, personally.
"I am seeing the same kid from a couple of months ago in how he is now. I don't see any change in his demeanour at all.
"I think Wilf is one of those nice and easy-going sort of lads. I don't think too much worries him a great deal - that is the impression I pick up of him, and that is certainly what I am seeing in his football.
"I think we elevate them (young players) very, very quickly. For me, Wilf is where he is at the moment - whether he has gone to Man United or stayed at Palace, I view him as the same player, who is learning the game, is maturing, will get better and better and hopefully will have a career with the seniors."
Zaha is part of the Young Lions squad Pearce has selected for friendlies against Romania at Wycombe's Adams Park on Thursday night (kick-off 7pm) and Austria at Brighton's Amex Stadium next Monday.
After that double-header, the 50-year-old will name his 23-man party for this summer's European Under-21 Championships in Israel.
Pearce has made it clear that he already knows most of the players he wants to include in that squad.
And he has indicated that Blackpool winger Tom Ince and Tottenham defenders Danny Rose, who is on loan at Sunderland, and Steven Caulker are among those players.
Ince and Rose are each unavailable for the opening game of the Euros due to one-game bans that relate to the trouble at the end of the qualifying play-off second leg against Serbia last October.
But asked if suspensions would affect his selection plans, Pearce said: "No. Danny Rose is too important to me to leave him out over a one-game ban.
"We have got Incey missing for the first game, but I think the only way I would deem that (that someone should not be selected for the squad) with my really important players is if they had a three-match suspension and missed all the group matches.
"If Caulker or Ince had a two-game suspension, I would still take them I think."
Caulker has had a two-match ban, also imposed after the Serbia game, lifted on appeal.
Ince, Rose and Caulker were all included in the original 28-man squad for the Romania and Austria contests.
But Ince has since been ruled out of those matches due to injury, as has Southampton defender Luke Shaw, while Caulker has been promoted to the seniors following the confirmation earlier this week of Rio Ferdinand's withdrawal.