[Nyororin]

I think you`re striving for the wrong thing.
Not that being a mangaka is an impossibility - but rather things have to be done in steps.

First, strive to be a better artist. This is something you should never stop striving for, no matter how good you become.
Then strive to be a better writer - a manga is nothing without a good story.

And while you`re on those, work on Japanese language. Japanese people in Japan speak Japanese. They aren`t going to have too much interest in publishing English language manga, even if it`s great.

There are a lot of things you need to work on before you can really say you`re striving to be a mangaka.