During their time as Teaching Assistants (TAs), graduate students develop a variety of skills, knowledge, and attitudes (SKAs) based on teaching and related facilitation experiences. As TAs move on to future opportunities, their prior experiences form a foundation upon which additional teaching experience builds. Presently, there are few tools to gauge pedagogical growth during graduate student involvement as TAs in a specific post-secondary course, or as a consequence of their participation in a specialized TA training or teaching program. We identified key factors that underlie TA development and designed a new survey based on these for TAs to self-assess SKAs that they bring with them from prior experience, and those that they develop or enhance during their time as a TA. We designed a survey to test how TA experience with non-traditional roles in a First-year Seminar in Science course, SCIE113, affects SKAs that can be used in future teaching endeavours. We administered the survey to 18 current and past SCIE 113 TAs as of December 2015 (representing the complete population). The results showed that TAs with similar levels of experience shared similar skills, knowledge, and attitudes. Those TAs with the most experience had greater abilities in roles previously identified as non-traditional TA roles. Others working with graduate students can use or adapt the survey questions to investigate and stimulate the growth and development of TAs in their course or program.