well to answer "when im supposed to start doing research": as soon as possible. now, what you should do is go to your school's website and read up on the research abstracts of all the faculty who work in your area of interest. it may help if you've already had someone as a prof before you ask to work in their lab. then, if you've found a couple that sound cool, start emailing them explaining that you want to get research experience, why you want research experience, and why you're intrigued by their research.
some profs won't let you start as a freshman (you haven't had any basic science courses yet for background, etc.), some will let you in as a dishwasher and then give you a project after a couple of semesters, and some (especially newly hired profs in desperate need of personnel and publications) will get you going on bench work right away. you just have to make your moves wisely.
oh, and one last thing, don't go to the lab that can pay you the most, or even pay you at all--i, for instance, work in two labs. i get paid to be a mindless peon in one, and in the other, i'm totally autonomous, have publications/etc. but i pay as a student (independent study--every school has this).
good luck!