There is no right time for every student to start undergraduate research. Some students start research between their first and second year in college, whereas others start research during their junior year. If you are interested in graduate school or careers in research, you should aim to start during your sophomore year. The most important factor in when to start is that you have the time to devote to the research.
Your initial start time may depend on the lab you join: some professors prefer that students start research in the summer (see below) and others prefer that they begin during the academic year. You can ask about this when you talk with professors about research opportunities available in their labs. If you are planning to begin research in the summer, you should begin looking for a lab in December. If you are planning to begin research in the academic year, you should start ot secure a position the semester before you intend to start.