Engaging in undergraduate research is identified as a High Impact Practice (HIP), an experience that improves student learning outcomes. In this paper, we report the differences in the relative rates of increase in skill and knowledge gains associated with early engagement in undergraduate research from students who have little to no prior research experience. We studied the relative rates of changes in novice researchers' perceptions of the progressive development of different research-related skills and conceptual understandings of their own projects, as well as how their attitudes, such as confidence in their own abilities as researchers, develop with continuous participation in mentored research. Knowing the progression timeline for various skills may help program administrators and faculty mentors plan for "just in time" provision of relevant resources and supports.