Come on in the water is fine. Serious the S3 is a great choice for your first android phone, specially if out get into rooting it and installing custom ROMs, there are tons out there, I will also say to look at the nexus 4. Nothing is better then the pure android experience.
Welcome to the green side.
Past Devices: Google Nexus One (sold), Samsung Galaxy S2 (sold), B&N Nook (returned), Samsung Galaxy Tab 7 (sold), Samsung Galaxy Tab 10.1 (On the Shelf)
Current Devices: Samsung Galaxy S3 (AOKP), Nexus 7 (Stock)