kant- space and time

Kant says, "When I speak of objects in time and in space, it is not og things in themselves, of which I know nothing, but of things in appearance, i.e. of experience, as a particular way of cognizing objects which is only afforded to man." He then says, "Objects of the sense therfore exist only in experience, whereas to give them a self-subsisting existence apart from experience or prior to it is merely to represent to ourselves that experience actually exists apart from experience or prior to it." This section made me think of a few things. First of all time. People say like from the beginning of time, so what is the beginning of time? The first time we used a watch or calendar?, the first time of humans? the first time of earth? Either way, these are limits. If there is a beginning to something that means there is a limit. The opposite would be if the earth was always here and then no body knows the time or how old eveyrthing is. We can guess all we want but we will never know.