Pre-Book Freakout

So I have done copious amounts of research on flights, visas, and timetables for the big trip. I know more than I ever intended to, and therein, I believe, is the problem. What is the problem you ask? Well that's simple, I am scared of making the big ticket purchase only to find out an hour later that I should have done something differently. My main concern right now is the timing. Timing has never been my strong suit, from birthdays to love to finals, my timing has always been a little off; like that time I forgot to turn in a final only to remember as I went to get another round between pool games. In this instance the dilemma mainly revolves around how long I ought to be going for. My life at the moment has consisted of day to day activities and the main way I keep track of time is my temporal relationship to the next soccer game planning, so the very thought of scheduling to be gone for 2 months time scares the crap out of me. Moreover, since I am off by myself as the master of my own domain rather than tagging along a guided tour I will invariably be responsible for planning my own life, an intensely gratifying yet foreign concept. So can I handle booking a ticket back to the states a full 58 days after I leave them...I sure hope so...I need to muster my courage or else i fear i shall regret it for the rest of my life.