The first round tie will be the winger’s last action before he flies off on international duty with Northern Ireland.
Whyte was part of a youthful front three – alongside Marcus Browne and Sam Smith – who tore Wycombe Wanderers apart on Tuesday night.
The 3-0 victory secured progress in the Checkatrade Trophy and now the 22-year-old, who moved from Crusaders in the summer, is aiming for more of the same in his first taste of the FA Cup.
“It means everything,” he said. “It’s a massive competition and is something I’ve always dreamed of playing in.
“We’re still confident and Tuesday night was a great win.
“They played three at the back which gave us a load of space. Me, Marcus and Sam Smith had a field day, so hopefully we have more games like that.”
United will start the game as favourites to progress, but there are only 12 places between the sides in the league pyramid.
They fell at the first hurdle to Sky Bet League Two opposition last season, at Port Vale, but Karl Robinson’s side have won more games in cup competitions than in League One this season.
The U’s boss said: “It is a banana skin, but if they beat us I don’t think too many people would raise an eyebrow.
“I love the FA Cup, I really do. I’m a traditionalist.
“When it comes around there’s a different smell, there’s something about the air in the stadium.”
Ricky Holmes (back) is the main doubt for United, who will not risk anyone with injury niggles.
Forest Green are expected to undo the changes made in their midweek Trophy defeat to Arsenal Under 21s.
Oxford Utd: from Eastwood, McMahon, Nelson, Dickie, Ruffels, Mousinho, Henry, Brannagan, Whyte, Smith, Browne, Holmes, Spasov, Heap, Hanson, Long, Raglan, Garbutt, Mitchell.
Forest Green Rov: from Sanchez, Gunning, McGinley, Mills, James, Winchester, Grubb, Brown, Archibald, Digby, Campbell, Reid, Morris, Worthington, Pearce, Williams, Rawson, Montgomery.