Is it possible to forget your whole life with amnesia?

...or say you were 17 and forgot everything from the last 15 years.

Would you have the mental age and capacity of a 2 year old and not remember how to anything?

Or would you remember words/what things are called but your life itself is a blank slate?Is it possible to forget your whole life with amnesia?
A number of years ago I was in a car accident, I had a severe head injury, I was in a coma for about 2 weeks, When I came out of it I didn't know who I was, where I was, or why I was, After about 8 months of intense therapy a lot of my memory came back to me, many of my memories in life are long gone, and doesn't look like they'll ever return.

It kind of leaves an empty feeling inside of you.Is it possible to forget your whole life with amnesia?
typically amnesia that comes from a brain injury is only the memory of person information and events.. you would not forget how to speak... unless there was damage to the areas of the brain responsible for speech but that is considered brain damage and not amnesia..... yes it would be possible with a brain injury to forget your whole life but more typical is when there is a trauma like a rape of car accident and people have amnesia of the traumatic event.... maybe a couple for hours. Havign amnesia of many years happens but is fairly rare.