Hallo, Franck. Unless you count the unborn, Millvina was the youngest survivor. From a quick look at the stats the oldest, I think, were Mary Compton and Catherine Crosby, both 64 and travelling 1st Class. The oldest person on board was probably 3rd Class passenger Johan Svensson, who was 74 and did not survive.
Of the crew, the oldest on board were the Captain and Dr O'Laughlin, both 62, and the youngest was bellboy Albert Watson, who was 14. The oldest surviving crew member was Chief Bathroom Steward Samuel Rule, who was 58.
[Moderator's note: This subtopic, which was originally placed in "General Titanica" has been moved here, with other subtopics addressing the same general question. MAB]