The Dink Network

This is just my opinion, but if time existed then everything would happen according to an exact timeline at the exact rate as everything else... a fixed timeline... but in reality, and especially in relativity, time is seen as a more flexible thing, and that time as we know it doesn't or probably doesn't exist... Take this as an example: Mass alters the space around it, with gravity and whatever else. The physical velocity of a mass in motion not only alters space, but also 'time'. e.g. A set of twins born the exact same day are the same age throughout there lives, correct? Let's say, one of these twins has a normal job, grows up never leaving the earth. The other twin, however, becomes an astronaut, and goes on a space journey many lightyears away on a high-tech ship that can travel almost at the speed of light. If the destination is 2 lightyears away, the return trip would be 4 lightyears, and if he is travelling almost at the speed of light, you would assume it takes him a bit over 4 years to make the return trip. But on his arrival, he has not aged four years at all, and is in fact now quite younger than his twin whom never left earth. How is this possible, if time did exist as we know it?