Not entirely. Without time, everything would happen all at once. And because events happen in sequence, it's that sequential nature that is what we know as time. It's no accident that time is described as a "timeline"; without a timeline, all events would take place at a single point, like you being a baby and a grandparent at once.
Time is ALSO a measurement, and it's the measurement system that we have come up with, relative to repetitious natural events as observed on this planet. For example, a year on earth = the completion of one circuit around the sun. Recently it was observed that one year had passed on Neptune between the time it was discovered in the 1800's and this month, 2011. A year for Neptune isn't the same as a year on Earth, obviously, because for Neptune to go around once, it has to travel a longer distance than Earth does to go around once.
If time didn't exist, both Neptune and Earth would be at all points around the sun at once.
Time is a human construct, quite possibly based on the human conscious and cognitive need for organisation and order. Same comes with the temporal concepts of day, night, month, etc.
Humans, for the most part, need to, want to, and try to make sense of things in order to better understand, which is where I think the concept of time came from. I'm sure some people believe it's an advantage and testament to our 'higher' level of intelligence compared to other animals, and others probably see it as a setback because we think too much and try to reason too much.
If I recall correctly, the current system of 60 second minutes and time units in multiples of 60 came from the Mayan or Aztec or Incan civilisations. It's amazing the kinds of things ancient peoples knew if you think about it. :)
Time is a mathematical equation designed to explain what we see, feel, and experience in our daily lives. It's a fundamental element needed to explain how things travel and move about space, both outer and right at home. Without time many scientific principals could not be explained or even theorized. It's both made up and an intrinsic necessity. It would exist without us but would be unexplained and on some levels less necessary. It both is and isn't at the same time. It depends on the way you use it.