Four months ago I decided that I would give running a half-marathon a try for the first time in my life.
Firstly, I spent a few weeks training, which involved workouts at the gym and running on a treadmill. When the spring came I could go outside and enjoy running closer to the nature. It was exactly three months before the target performance. Each week I was doing 3-4 workouts to boost my condition, which included one slower long run and one basketball 1.5 hour training game. One month before my first official half-marathon appearance I was able to run 18 km at a sustained pace. That gave me confidence that I could complete the target distance of 21.095 km.