Chinese kung fu is about defence and improving health. Tai Chi is a very sophisticated art, but if all you're interested in is just fighting then go elsewhere. Its obvious Tai Chi is not for you.
u can't really get into tai chi aiming to be good at fighting with it, you'd get fed up way before you reached that level. just enjoy the other huge benefits of it, the fighting benefits might come much later. if you want to be good in a scrap take up a hard 'external' fighting art.