Ahead of one’s time—(of people, new ideas, etc.) too advanced to be accepted by one’s contemporaries.
- Men who are ahead of their time can lead the present into the future.
Before one’s time—
1. before a person was born, had arrived, etc.
- There was at one time a little cinema, but that was before my time.
2. before the due or expected time.
- His poverty, and continual harassment by the authorities had made him old before his time.
3. = ahead of one’s time.
- Robert Owen, with his enlightened ideas on working conditions in factories, was before his time.
Note: The expression is not antonymous in meaning to the phrase not before its time—used of smth. that should have been done long ago.
- At last they are installing electric light in the main streets, and not before its time.