Answers:
"You were born before your time" means that you are far ahead of the age in which you live. A good example would be Leonardo da Vinci, who lived some 500 years ago, but was so far ahead of his time with all his inventions, that he probably would have been right at home in the mid-Nineteenth Century.
If someone says that you were born before your time, you might take it is a compliment to your intelligence.
Look around you and you can see the opposite saying (which I am now making up) to be true: He was born long after his time. There are plenty of knuckle-draggers out there. However, let's think of the positive. Most people seem to fit in quite well with the times, and these could be considered to be born within their timel But, frankly, these people aren't as interesting as those who are 'born before their time'.