A judicial review into the project's funding has been dismissed, allowing the Championship side to press ahead.
"It's like an early Christmas present," Groves told BBC Radio Cornwall.
"The good news means that we can now crack on at the beginning of next year with getting the refinancing [of the club] organised."
Pirates have been attempting to make progress with their proposed 6,000-capacity ground for several years, but it has been complicated by Cornish football side Truro City also wanting to build a new stadium.
Asked when work on the prospective stadium will start, Groves added: "That's the question - my guess is sometime in the middle of next year.
"The first stage is refinancing and recapitalising the Pirates, the second is around the stadium design and building a sustainable business, and the third phase is around a rugby partnership."
The rugby partnership is with Super Rugby franchise Waikato Chiefs, whose chairman Dallas Fisher is visiting England in January.
Groves says there could be potential for player swaps with the New Zealand side in future.
"That is an idea going forwards, probably a couple of years down the track," he said. "I would describe it more like IP [intellectual property] swap - coaches, and maybe one or two players.
"The first thing we've been focusing on at the moment is steadying the ship. I don't think people realised how bad the financial situation was at the end of September - the Pirates were pretty close to going into bankruptcy or administration."
Cornish Pirates director Colin Groves has estimated that work on the Stadium for Cornwall will start "in the middle of 2017".