Falcon for sure
Shark Bay likely to be 40 deg and windless, you may get lucky with early morning easterlies but they'll be gusty and crappy.

Falcon is an excellent location - close to lots of lovely flat water spots on the Mandurah Estuary for gybing practice. There are spots that work on any wind direction, and always plenty of good company on the water. You will need a weed fin. Also plenty of other attractions in the area, and a world famous bakery!

In February Albany is another consideration. Lilacs in an Easterly can be super flat and fast. Steeply raked weedfin a must.

Shark Bay will be very hot and there is the risk of cyclones.

Sailing lots in Falcon for 12 years and shark bay for 5 yrs or so, you'll get better windsurfing and better seabreeze winds in Shark Bay in Feb than Mandurah. However, when its hot it can be horrible in Shark bay. If you could go at short notice I'd keep an eye on the weather forecasts, and go where its windy. Albany in feb can be sensational too. The thing about Falcon is, if its not windy there's lots else to do. Just thought I'd throw my 2 cents in, as every other responder had written shark bay off, whereas in reality its better than Falcon in Feb.

PS. I live in Falcon

PPS. If all places were equally windy in Feb, I'd choose Albany!!!!!!!