Kha is a bit of a reach typically for people in bronze. Honestly I never recommend squishy champs for people that are still learning the game since they require really quick decision making and on point mechanics. Playing something tankier gives you a chance to 'experience' team fights a little more and grow your understanding of the game.
Based on your stats though, it looks like if you spam another 60 to 100 games with him you might have a chance of crawling to Silver since you are winning more than losing with him. If you want to play an easier champion that will help you learn the game then try something like Amumu, Gragas, Hecarim, Jarvan, Jax, Nunu, Rammus, Rek Sai, Sejuani, Shyvana, Skarner, Vi, or Volibear. Those are the ones I usually recommend for people that are learning the game because those champs make it easier to focus on the bigger picture rather than what is happening immediately.