I never believe in diplomacy.
Ek time par rook sakte hai ke nahin...... what that mean in scientific scenario.................... you want to remain younger forever ? if that so.................... my answer is NEVER
Theory of relativity shows that both space and time are curved. If we can move forward and backward in space we can move forward and backward in time too. Einstien's theory can't deny that fact by any means.
If time is relative, being young or old is relative, and everything is relative, then what do you mean by time travel unless time can exist at all the points (Past presnet and future) simultanously? Whole concept of negative and positive time is based upon the expanding universe and the existance of black holes. These are two states of matter at astronomical scale. It does not prove that one can move along the time curve as per wish and under controlled manner. If you are aware of Time Travel Theory where one has total control on the speed, direction etc , please ellaborate the details.
RK^2