I don't believe in the concept of "starter" snakes. If a ball python is your dream snake, get a ball python. As long as you do plenty of research and are willing to spend the time and money for a proper setup, then you will have a thriving snake!
As others said, it will be ideal if you set up your enclosure with the correct temps and humidity before the snake arrives. That way things will be less stressful for both you and the snake
That's spot on. Tweaking your temps can be tricky in a brand new setup and the wild fluctuations you will most likely experience are not good for your snake.