When I was thirteen, I participated in a three-week study abroad program in Toronto. With my homestay mom Rosario and two other roommates from Germany and Mexico, we took walk every evening to the Mississauga campus of University of Toronto near our home. Since then, going back and study in this beautiful, modern, multi-cultural campus has become the biggest dream of mine.
I know you are short on time, but perhaps rework your introduction. I am a firm believer in answering essay prompts explicitly and not deviating too much from what is asked. You begin with a nice story, but right away you aren't answering the question,
Describe your principal activities and interests beyond the classroom.
So what are your principle activities and interests beyond the classroom? Can you summarize your interests into a a couple sentences or a short paragraph?
Your third paragraph is confusing. You begin by stating some organizations that you would be interested in, but you don't go into detail after that. However, I like the structure of this, as it is answering the essay prompt more directly:
I always believe love can only be spread by extending our help to people in need. Through Toronto's Serve and Learn Program offered by the Center of Community Partnerships, I will have the opportunity to work, learn, and get inspired with non-profit organizations, community agencies, municipal governments and schools.
Also you mention "the first thing I will do as a junior is..". I would suggest putting that in the beginning of your paragraph...since it is the first thing you will do...
Basically, your third paragraph needs more structure. For example,
Extra-curricular/organization etc. will play "some role" in my life as a trinity student, because _________. I enjoy/ have experience with/ am passionate about etc. _________, and look forward to __________.
You don't need to list too many examples, just two or three strong ones to get your point across.