Like the above, I think it is hard to put a date on when one would get engaged.
Usually, when you are younger, you say wait 5 years before making a decision. I had a friend who got married after knowing his mate half his life. Age 14 --> 28. Then there are those who are doctors who fly back to the motherland and meet the girl for 2 weeks and then get married.
I don't think there is a right or wrong answer on dates. If you are sure, and know what you are looking for.... 2 weeks could be the right amount. (Not for me... but hey...).
If you are not sure, then its definitely not the time yet. Usually both sides will know it's time when they want to get married.
Best of luck on your escapade. :^)