Comparing/Contrasting this with Before Sunrise

There are some similarities with this and Before Sunrise. Get over the "she was 14" and think about it. I recall Ethan Hawke's character was supposed to be 23. Is it that people of that generation were just so much more mature at age 23 than 28 year olds are now? I recall when I was age 23 that we wanted to be fully mature adults, living along, traveling in these big cosmopolitan cities and handling it. So why are people these days so immature, rude, foul mouthed and in various levels of arrested development? Is it generational? These guys were totally messed up and immature 28 year olds though.

I think this could have been a beautiful romance had only she been 17 or 18. What do you think about its similarity to Before Sunrise and tell me something other than "not at all."