You need a license and the requirements vary from state to state. Your 12 ga is a good choice and if it has choke tubes use a full choke or the tightest one you have. I like #5 shot but there are many people who use 4 or 6 and some use the combo shot. Easiest call to master is a box call but the cheapest is a mouth diaphram call. If you go you will probably get hooked on the sport and find yoursellf buying several differewnt calls. Safety is real important and hopefully your friends will instruct you on the different aspects of turkey hunting safely. Best bet is to go out the first few times with an experianced turkey hunter and learn how to call and set up. Good luck.