Einstien's Theories on Space/Time

As I understand it, energy can be used either for accleration through time, or acceleration through space, your total energy always equaling the same whole.

But acceleration through space is defined in relation to time; time squared, in fact. Does this mean that moving through space at a high acceleration will make you essentially ageless?

Also, since e=mc^2, and light is massless, it is moving at the maximum speed of reality, making light essentially timeless, right?

thats it, my friend didn't belief it but it is, so here is a more simplyfied way of the weight thing(he tough, if you go faster while on a machine that checks ya weight you can proof ya get heavyer, anyways):
person A weighs 100kg

if person A went on a spacecraft and went 5G, he would weigh immensifly more, yet, he would still be 100kg, no more no less(unless ofcourse he shit his pants) but the gravity pulls hard on ya + the speed so N will be bigger, please correct me if im wrong but i think you can say it like this :)