You pretty much missed this party, sorry.
But to answer your question no you don't have to be at the computer. It runs itself. At this point in the game though, you would pay more for electricity then you would mine, unless you went out and purchased specialized mining equipment.
No one can ever predict how and when Bitcoin mining will be at a safe and stable state. Speculations and factors such as mining difficulty and volatility could bring huge impact to your asset. Just like any other investment, it can potentially lose or gain.