The 22-year old striker joined the promoted Eagles for £8.5million from Peterborough United this week and is now gunning for the top flight after commencing last season playing in the Conference North with Bishop's Stortford.
"I can't believe what's happened," Gayle told Sky Sports News. "It's so exciting to be playing in the Premier League next season.
"I just can't wait for it to get started and get a few games under my belt. It's just a dream come true really.
"If you'd told me a year ago I could be walking out at Old Trafford, it is unbelievable.
"I'm most excited about playing against big players, seeing what I can achieve and playing against Manchester United."
Of the pressure of playing in the Premier League, Gayle added: "I'm going to handle it because I think the people around me will keep my feet on the ground.
"It's difficult to deal with all the attention I've been getting but I should be fine."