Newbie

We have recently been sent an estimate for the building of an extension onto our pavilion. The estimate is for 65.53 m2 to include two bedrooms and a shower room. It includes 5 double glazed windows with shutters, a large sliding patio door with electric shutter, all the bathroom fittings, tiled floor through out, painting of walls, all electrics, plumbing, extension of outside patio and of course the main structure of the building. The cost is 78.700,00 euros. Does this sound reasonable?