Imagine you're a CPU and your perception of time is in clock cycles. Would you be able to give an ordered sequence of events of all the things that happen before your clock generator starts, e.g. voltage ramp-ups, etc?
That is a perfect example, and i think it illustrates a few things.
For the CPU time started on the first tick of its clock, but the tick of that clock is still tied to a time dimension in its parent universe. the term "Before" still makes sense when describing the sequence of events as the power button is pressed and then the electrons race through the wires to cause that first tick of the clock. now the CPU may not have adequate terms to describe this or understand what a power button or electrons are, but it is readily apparent to us as outside observers.
Being stuck inside the CPU would have a very difficult time figuring out the mechanisms that drive it. however some of our theories of quantum mechanics allow for higher dimensions and for structures to exist outside of our universe. And we even have experiments set up to look for evidence of some of these structures. such as polarization in the cosmic background radiation. if our universe isn't the outermost layer and is a brane in a higher dimensional universe, such as some versions of quantum mechanics suggest, then time may exist in some form outside of our universe. how this time works may not be entirely recognizable to us, but saying "before the big bang" could still have some meaning.
maybe another example. if i travel to the south pole of the earth i can't go south any further. however i can still travel further away from the north pole by jumping. by jumping i may not be any further south, but i could be considered less north. so what is before the universe? i don't know, lets climb to the bottom and jump and see where we end up.