You're correct that the observation of time dilation requires the availability of information. In the scenario you described, where you are traveling at a significant fraction of the speed of light from point A to point B, the effects of time dilation would only be noticeable when comparing your clock to a clock that remained at rest at point A or point B.
For instance, if you have a synchronized pair of clocks at point A, and you take one of the clocks with you on your high-speed journey to point B, upon your return, you would find that the clock you carried with you has ticked less compared to the clock that remained at rest at point A.
The difference in the readings of the two clocks would indicate that time passed more slowly for the clock in motion relative to the clock at rest. However, this can only be determined when the two clocks are brought back together and their readings are compared.
From your own perspective, traveling in a spacecraft at high speed, you would not directly observe your own clock running slower. Time dilation is a relative effect, and you would perceive your own clock to be ticking normally. It is only when you compare your clock to a clock that remained stationary that you would notice the discrepancy.
In practical terms, the measurement of time dilation in high-speed scenarios relies on sophisticated experiments and technologies. For example, experiments involving atomic clocks or particle accelerators have been conducted to validate the predictions of time dilation made by theories like special relativity. These experiments involve comparing clocks that have undergone different accelerations or relative velocities to measure the differences in the passage of time.