Why do you want to apply for international student program?
-> First of all, it's just my old hope. = Before, it was supposed to be just a thought. When I was in university, freshmen student, = When I was a freshman in the university, I had a dream to go study abroad. But there were many obstacles in front of me. What I mean is that I don't have = didn't have the time to study English continuously because I was so busy working part-time job and studying my major field = with my studies as well as my part-time job. There were many people who was = were speaking English very well, and as a result I was always intimidated in language field = by it/them. But after entering the grad school, PUTS, I heard that my grad school offers international student program. Later I heard = After hearing/knowing about this joyful news, I started studying English although this process is so difficult.

Note: blue = your sentences

           red = my corrections

           yellow = omit/do not include