As a sophomore in high school, it is extremely early for making career decisions. Fortunately, you have a lot of time to explore many different areas and you won't have to commit a decision for a long time.

It is true that becoming a psychiatrist is a much more demanding path.

As for time needed:

Psychologist (if you get an advanced degree, such as a PhD) you will go to a 4 year college after high school, and then attend a clinical psychology graduate program. The graduate program will take around 4 years. I'm not entirely clear myself whether the internship experience is part of the PhD process or an additional year after you've completed your PhD. As I'm not a psychologist, I'm less familiar with their training requirements and process.

Psychiatrist - you will go to a 4 year college after high school, and you will need to complete all of the pre-med coursework. This is a very rigid set of courses that are required to take the entrance exam for medical school. You then will attend a 4 year medical school, which is a very rigorous experience. It generally includes 2 years of basic science coursework and 2 years of clinical rotations - all of which are very intense. You will then apply to a residency program in psychiatry, which is a 4 year program. They vary in intensity, but usually at least 1-2 years of the work will be pretty intense and maybe 1-2 years will be less intense. Once you finish residency, you can practice as a psychiatrist.

Overall, I'd say that the differenc in time required between a PhD psychologist and a psychiatrist is maybe 3 years, but the level of intensity is far different and the daily work as a professional will be quite different.

Again - it is really too early for you to spend too much time worrying about your career. I would suggest you focus on doing well in high school and picking a college that provides a good liberal arts education and has a good pre-med track, in case that is the route you decide to pursue.