@ 747 Forever
When you are determined to be a pilot you should fly whatever comes on your way.Let it be a Cessna, a 767 or a F-16. And like the other guy said there will be a stage when you will have 1000s of hours and you can find yourself on a 747 Flight deck that day. you are still young I understand that, even I was like you when I was around your age I always wanted to fly big Aircrafts that fly very long distances, Now, I am doing that! But I didn't achieve that when I was 18, there are stages you need to go through. Sometimes you can reach that level very very fast but on the other end it is going to take hell of a time. And Long Haul Flight is not for everyone. I know over 10 B777/B747 pilots that I worked with left to fly B737, A320 and even ATRs(no joke). So its not everyone's thing to be on long hauls. The average hours for most of my flights is around 8 to 10 hrs. If you are single no problems but if you are married with kids and they are not willing to travel with you all the time then its a big problem. Its tougher than what many people thinks.