Not everybody is built for that. You need to understand what it is like to live in a lab in order to see whether or not that's something you would do. You have to really like what you're going to spend your time doing. So it's really important to spend some time in the lab. If students haven't had undergraduate research experience they should go work as technicians for a couple of years.
Undergraduate research is part-time at best.
In graduate school you spend 40-50 hours a week 'pushing' test tubes. Some people can't stand that. It is important to know that before you spend 4-5 years of your life in graduate school. Some people ask me what I do and I tell them I am a scientist and they're always interested in what I study. Most people believe that we the reason we do what we do is to cure diseases.