The Staffordshire official will take charge of the showpiece event for the first time with Stuart Burt and Andrew Garratt running the line and Michael Jones as fourth official.
"We can't afford to make a mistake," Dowd, who was fourth official at the 2006 FA Cup final when Liverpool beat West Ham on penalties at Cardiff's Millennium Stadium, told FA.TV.
"Players can make mistakes and then put it right later but if we make a mistake we are in the spotlight straight away.
"Every 30 seconds I'm always chatting and talking (to his assistants) just making sure everyone's all right, geeing them up - and they do the same for me.
"If something's gone wrong and you are aware after it's gone wrong you just make sure you get the next one right."
Of the first decision he has to make he added: "As long as it's a little one it'll be okay; if is a big decision it will be really important.
"An early throw in will be good - start up nice and slow and build up."
Dowd, who has previously refereed the 2010 League Cup final and 2011 FA Community Shield, admitted his appointment to the final is not something he has had the chance to enjoy yet.
"It still hasn't sunk in yet - until I've actually done the game I won't believe I'm going there," he said.
On how they approach the game from an officiating point of view Garratt said: "As long as we are all not looking in the same place that is the most important thing."