You'll face a lot of obstacles at first. It's all too easy to stop when the weather turns cold, when it rains or snows, or when you feel the aches and pains of starting. You haven't had to deal with these things before and the temptation to quit is strong. Your running may also be threatening to your less active friends. The transition period, however, can be unstable and uncomfortable for both.
Social reinforcement makes it easier to establish the fitness habit.
One good approach is to find a group that meets regularly. Or you can make a pact with a friend who drags you out on bad days and vice versa. Races and fun runs are great opportunities to meet people. At times, you may not progress as fast as you expected. We Americans are traditionally hyperactive and impatient.