About my future

Recently, I often look to my future. When I was a child, I wanted to be a grown-up as soon as possible because adults can do what they want to do and choose anything what they should do.That is, they have the freedom of their action. However adults should take the responsibility of everything. I keenly realize about that lately. I'm a student now, but I have to work two years later. Before that, I have to decide my course.
I'd like to work using English, if possible, I want to be a English teacher. However I have no confidence whether I can be a good teacher for students. For example, I don't know effective teaching to easy to understand. I want students enjoy English. Enjoyable English cause motivation, I think.
This summer, I'm going to go teaching practice.So I want to put emphasis on enjoyable activity in the lessons. If you have some good idea, please advise me!