I think you mean “I didn’t know what I was going to be in for” – you didn’t know what to expect.
I would also change “stood for” because to me it sounds strange to say a course “stands for” something. I might say:
I really wondered what the IS 101 course at my university would be like.
- but it means a bit more than just 'what to expect'; it's 'what sort of treatment/experience/punishment/weather... to expect'. The 'punishment' option has been enshrined in an idiom: 'to be for it', as in 'They'd better not find out, or else we'll be really for it.' The 'for' here is always stressed - /'fɔrɪt/