[GoNative]

To be honest I reckon you're friends are right in that it's a little early to commit to anything. It's great to have a goal and start working towards it but 3-4 years away is a fairly long time. How many of those friends will still be around? How many will have moved on, have careers,gotten married, had kids, etc, etc...
If I were you I'd just worry about organising the trip for yourself as a first step. So yes you'll need to get a job as it's not entirely cheap to travel overseas, certainly far more expensive than just staying at home. And of course you'll need to get your passport. So work out the things you would really like to do, how long you would like to stay. Work out a daily budget for the trip to work out how much you'll need to save to be able to do it. Then in a few years when you've got the money saved and a pretty good idea of an itinerary then go to your friends and try and sell them on the idea. To be honest organising a trip for up near 12 people can be a huge undertaking. I'd plan for a lot smaller group. Something like only 1 or 2 others. If more want to jump onboard last minute then that's fine.