Hello! I'm Kana Takagi from Japan. (I think it will be better to put it in one sentence)
I am a junior high school student. I have a sister (I think this sentence a little bit not fit here, how about move it next to your first introduction?). My hobby is playing tennis. I'm a member of the tennis club. I'm studying English because I want to speak in English and to make a lot of friends, but (don't put but or and to start a sentence) I don't like studying. My goal is to be able to speak English!
I will study English very hard for that!!
I'm also on my way to learn a better grammar so pardon me if there is also a lot of mistake here