Public to private school?

next year im going to be a freshman and i want to transfer to private school. im currently in public school and i dont really like it, plus the high school in my town has a little less then 2000 people in it. while the private school has like 40 people in each grade which probably makes it easier to learn. is it easy to transfer from public to private? is private more preferred then public? i really want to do good in high school because everything counts into getting into college. and is there a higher expectancy rate for universities? and how am i supposed to tell my parents i want to swich (the open house is in 2 weeks)