Matthew McConaughey and Anne Hathaway in 'Interstellar. '. After leaving Murph, Cooper departs on another TARS mission, aiming to reconnect with Amelia. While viewers don't see the pair together again, Amelia removes her helmet and breathes on a newly discovered, habitable planet.

Roughly 10 years prior to the launch of Endurance, she and Particle Physicist Dr. Wolf Edmunds, had fallen in love. Cooper had suspected her feelings towards Edmunds when discussing the destinations they were heading to, knowing that her affection towards Wolf would make her biased to his planet.

Back on Earth, Brand confesses to Murph the true purpose of the mission – to colonise another planet, rather than data that could help the Earthlings. Brand dies soon after, leaving a devastated Murph to question her father's reasons for leaving her and her brother.

When he returns to the Endurance he receives Murph's message that she is now the same age as Cooper when he departed. This means he was 35 years old when he left Earth (which is a little hard to buy, but anyway). Now, by our assumption, this means that Amelia Brand was aged 27 or less at that time.