Yeah common mistake made by most people who start a reef tank. So tempting, all the nice fishes in the store you just want to have them all. Too many too soon. So do read up and be patient otherwise you will conclude that reefkeeping is difficult and give up. That will be a waste of time and money. You also mentioned about going overseas? Not advisable to start a tank and then go away so soon. First few weeks of a new tank is critical. Have to monitor it closely to make sure all is going well. Well hope you will learn to enjoy the hobby and all the best.