I would advise myself to do my research on schools and not just pick anyone based on location and school hours what's convient. I would visit the school for a day to get a feel for it first before i decide to agree to any terms and start attending that school. Also I would get the history of the school and staff to make sure they have the ability to teach me all the skills that's needed for the degree. I would also compare pricing between the different colleges. I would maybe walk around campus as well and do my own survey on how the students feel about the campus and ways to approve them. As far as the trasition process I would just have to make sure I give myself that mind set to be ready mentally to go into a whole different world of new people all trying to strive for the same thing a better future for everyone around them. Most of all I will tell myself to stay focus on my school work because it's very easy to get distracted.
I would tell them to hang in there to get through the tough times. High school is not easy, but if you can get yourself to through it and motivate yourself to continuing on to college, it would be the best thing you could ever do for yourself. Transitioning from high school to college would be alot easier if you start your self disipline early in high school.