I disagree with this. It's important for living beings to receive the Dharma and the more Teachers there are, the better. It seems to me that the OPs motivation is a good one and even though he says his bodhichitta is not pure, someone with compassion and a good understanding of the Dharma can help others, even if they only read from Dharma books by well established authors. You don't have to be a Buddha to be a Teacher.
Even animals can benefit from hearing the sounds of holy Dharma, so it's not wrong to teach if your motivation is good.
But people have to know their limits and they must have proper Bodhicitta.
And skillful means. Imagine a wannabe teacher creating aversion to Dharma in someone just because he didn't know how to present it properly. That person could have met the Dharma and succeeded if he had a good teacher, but because of a bad teacher this person created aversion to it. The karmic outcome can't be good.
I think one has to focus on being a good practitioner. A good practitioner will one day become a good teacher if the circumstances allow such scenario. The motivation of wanting to help others offering them the greatest gift is very wholesome. To get to the point of really being able to do it, one must focus in becoming a good practitioner and the rest will happen naturally. A good practitioner is always a good teacher by his own example if not by anything else.
Wisdom, you motivation is great, but be very careful so that you don't let your ego sink its claws deep in the best thing you have going on.
Let me just share with you a bit of my experience. There was a time when I envisioned to become a Dharma teacher in the future. The more I practiced, the more I understood that I was doing things upside down. Being a joke as a practitioner and thinking about teaching... what a laugh! It hit me one day, and it hit me hard. I've dropped all those ideas about teaching, opening a Dharma center and all that stuff.
I was being a fool and risking ruining my practice. How could I even think about such thing when I definitively needed to become a decent student/practitioner? I was being worse than the character of the "Famous Moon" tale. Those projects were all based on assumptions, one of them being that I would become a good practitioner... however I had no idea about what a good practitioner was supposed to be, as I was finding out through... practice! So one day it went all though the window. All those fantasies and projects that were lead by my new ego driven Buddhist layer. What a relief! As I liked Dharma and thought it would be valuable to others, my motivation was sharing this, so I studied and tried to progress fast. I came to realize that we have very subtle hindrances nested in ourselves. I can't share what I don't have. So, to the cushion and to the books just for the sake of learning and practicing, without future expectations, projects, fantasies. Focusing in each day. Otherwise it is like being in the kindergarten and thinking about becoming the President of the USA. It's funny if we're kids. Not that funny if we're adults. So each day to its own, I thought. It has been like this till now and to this day I think that was one of the best decisions I ever made concerning my practice. More than 10 years have passed and I'm still not even close of being considered able to teach Dharma. I'm not even sure if I'm already more than a half decent practitioner, but I suspect I'm not. So much for those teaching fantasies that were nothing more than a waste of valuable time!