How do I know I'd be good at management? People tell me that.

 IMO IME

1. There are at least four major Career Concepts of which only one, Linears, are suited for leadership/management positions.
2. Over 2,000 executives in my seminars have seen Experts ruined by promotion into management. The transition from Expert or Spiral to Linear positions requires a fundamental VABE change from “if you want it done right do it yourself” to “you can get more done through others.”
3. There’s a Career Concept self-assessment tool on my website, Level Three Leadership
4. Career success is a function of goodness of fit between who you are (the hand) and the demands of the job/career (the glove). The odds are that an Expert or Spiral who takes a Linear job won’t do well.
5. The definitions of success and the core VABEs of each of the four major Career Concepts differ.  VABEs for Linears:  'I can get more done by organizing others.'  For Experts, 'If you want it done right do it yourself.'  For Spirals, 'I'm getting bored.  I need to find something new that will stimulate and challenge me.'  For Transitories, 'It's getting to be time to get away and follow my true passion for a while.'  
6. Definitions of success: Linears: Moving Up.  Experts: Craftsmanship.  Spirals: Learning.  Transitories: My trade allows me to enjoy my true passion in life.
7. Testing as a Linear is no guarantee of managerial success. Then one needs a robust, clear and inspiring CHARTER to motivate people beyond simple rewards and punishments. And a host of other skills.
8. If you truly enjoy creating inspiring purpose/mission, visions of what you want to create and convincing others of the power of your charter, then you might make a really good manager.