1) You will sleep less than you used to. ( Apologise to your partner before you start - or your mum if you still live at home!)
2) You will code less than you used to.
3) You will quickly learn that you don't know as much as you thought. Don't take this the wrong way. You can not know everything. If people around you are teaching you things, you are in the right place. You don't want to be somewhere where you stop learning.