I'm not too worried about bears, wolves or bobcats. But if I see a guy in a clown suit and I'm more than a mile in from the trial head, I'd probably pee my pants!
Start out just doing day hikes on some local nature trails or bike paths. Get as much or a s little interaction with nature as you like. Once you start to feel more comfortable maybe try out a campground. Get to know your surroundings. About an hour before sun down a lot of the night critters start getting active. You can spend a little time there without spending the night. This way you can get to know what is out there without the worry of complete darkness.
Frogs, raccoons, owls and bugs are nocturnal creatures and they are very soothing to listen to once you know what they are.
The biggest hurdle in this is what is in your mind. You need to each your mind that most of the things that go bump in the night usually do so because they are too vulnerable to be out in the day time. Darkness is their protection and they are afraid of us who are active during the day.