Transfer or not?

I am currently a freshman in a 4 years college and I plan to transfer and attend a prestigious college (USC, UNC, etc) during the fall semester of my jr year. I am trying to get a GPA of 3.7 or higher before I transfer, however most of the professors in my major grades very tough at my current college. I think the highest grade that i can get before transferring is a 3.5 or 3.6. Would it be wise to transfer to a community college for my sophomore year in order to ace my grade so I can have a higher chance of getting into a prestigious college during my jr year? Or would this actually jeopardize my chance since the college see that I already attended 2 different schools.

I would like to apply as a transfer student to target school before my junior year but my high school grade is not that great. That's why I want to apply later because once you complete 2 years of college the the high school grade doesn't really matter when it comes to transferring.