Well, CCA is about time management. I have friends who are still
in EXCOs at Year 4, and on their way to 2nd Upper/1st Class.
You can take things easy, just don't forget your basics like
handing up coursework and taking lessons seriously.
It's a good time to explore the CCAs IMHO. And as for Profs, they
depend on the individual nutty professor. 
