You should be commiting your code at least once per hour, and at the end of the day. If you only work 1 day (8 hours) per week on this project (really, you should work more than that) you will have at least 12*8 = 96 commits in just these first 3 months.
Some basic rules:
- Never commit something that does not compile or is super broken.
- Commit whenever you "finish a thought": implement the first version of a new page, get that function to read from the database, get that form to show, etc.
- Push every day, at least.
- Pull every morning, at least, unless you really are in the middle of something. Resolve conflicts as soon as possible
See this stack overflow question and this programmers.stackex question for many other people who agree with me, well, rather, I agree with them. But, for this class I additionally require you to commit a lot so you can get comfortable with the process and so we (your team and I) can see your progress.
Those of you new to the class will want to read my Git and Github slides and pointers.