Once a year, a friend of mine shows the kids in sunday school, the cantaloupe drop test with and without a helmet. Normally that is all it takes to get the kids asking about helmets. I have broken two ribs mountain Biking and a buddy just broke 2 ribs and his collarbone avoiding a pothole. The helmet absorbed the crash and left him with a slight contusion. The EMT captain told him the helmet was destroyed and he'd be in serious condition if he lived, had he not been wearing one. Definitely get a good one with lots of foam pads to absorb the sweat. I'd start out slow, with a couple rides to get yuor legs used to riding as well as all the other parts that are going to be screaming in agony.
I usually cycle at 0500 in a very rural part of Kentucky. In 20 miles I might see 10 cars. I listen to music, turned down low with open ear phones to hear approaching cars and I have a helmet mirror and a bar end.
When I ride at normal day/evening, I never wear headphones, simply because of the traffic.
Good luck and hide your credit cards, cycling is addictive as is buying upgrades.