Ceredigion council plans to auction the site of former Ysgol Dyffryn Teifi in Llandysul, which closed last term, for development.
The council cabinet meets on Tuesday to discuss the sale set for 30 September.
But a new group, Plant y Dyffryn, wants more time to draw up a bid to buy it.
The site has a price tag of between Â£250,000 and Â£300,000, with proceeds earmarked for the new-build Ysgol Bro Teifi school which opened this month providing education for three to 19-year-olds.
Leah Williams, one of the founders of Plant y Dyffryn, said "any developer could come in and squeeze the community".
She said: "Llandysul is so small and so Welsh it would just tip the balance.
"There are eight acres of land on a large site with plenty of potential," she said.
Plant y Dyffryn is looking at the example of the Cardigan community venture 4CG in order to raise funds to purchase the site, and then run it.
It took over the Pwllhai site in the centre of Cardigan in 2010, and turned it into a car park to generate income from parking fees with buildings and workshops leased out to small businesses.
A public meeting was held on Sunday when Llandysul residents voted to call on Ceredigion council to delay the process of selling the school site.
In response, cabinet member Gareth Lloyd said that if the cabinet delayed the process of selling, then they would consider offering help to the community with their application.
A group has called on Ceredigion council to delay plans to sell-off a former school site so it can bid to buy and retain it for community use.