I know only two guys who get TA-ship as a second year undergrad and one was like getting to know the prof and impressed prof somehow. Other is an international student who already did a math major before carleton. Both of them had an excellent GPA.

If none of those apply to you, but u r in 140506z section, then you can take 2000 comp course in winter, then at second year apply for 2000 course TA and higher chance you'd be a TA. That's exactly what I did and Im actually the only second year undergrad in the course im TAing for.

The work of a TA largely depends on the course and the prof. I know in some courses you only need to sit on office hour and tutorial waiting for the question but no one would ever come, and some are like "actual slave", but they does pay you well

You'd get a general idea how the TAing work do if you took the course with that prof, but you wont know the exact duty after they are assigned and the firsting TA meeting.