From this imagery earlier, it certainly looks like it. It is certainly wider than the Florida Peninsula, and it’s diameter looks to be as large as Florida is long.
From the National Hurricane Center at 11PM EDT tonight:
Hurricane-force winds extend outward up to 75 miles (120 km) from the center, and tropical-storm-force winds extend outward up to 185 miles (295 km).
Florida is 500 miles long and 160 miles wide at its most distant points.
That includes the Keys and the panhandle. Using Google Earth, I measured the length of the Florida peninsula (minus the Keys) and came up with ~391 miles.
Measuring the size of Irma, based on the densest cloud bands, it shows ~528 miles in diameter from outer dense cloud bands through the eye. I also did a measurement across the panhandle from Tampa to Cape Canaveral and came up with ~139 miles.
hurricane tropical storm force winds extending “outward up to 185 miles” according to NHC, that means that if the storms holds in strength, the entire width of the Florida panhandle may get tropical storm force winds (39–73 mph, 63–118 km/h). That’s sobering, especially in light of this track projection:
Irma is certainly bigger than hurricane Andrew, seen here in 1992: