Why would my mother and brother tell me I will never be able last out there on my own?

I am twenty, still live with them, they almost scoff about the fact. I am very shy. I have suffered from depression from a very young age living at home. I was always alone, protected in the confines of the house but at the same time ignored, ridiculed, insulted, degraded, laughed at, humiliated, disrespected, molested, violated, condescended, put down from a very young age. Any good memories I might have have been completely tainted by the constant stream of bad ones. I am the youngest in my family of 6 and my predominant sense my whole life has been 'being pushed away, bullied, rejected' by all of them in various forms. Why is this? They try to skew my perception of the past by making me think that I am the one at fault, I am the nasty one and they are all right as in alot of sense they have numbers on their side. It is simply not true. If I have a memory from age four whereby I was blamed for something I didn't do to a point I was balling my eyes out crying and forced to crawl on the floor for two days searching for a piece of gear I supposedly lost (even though I was a good girl who never lied) and was threatened with a belt by my parents who seemed to find the whole incident entertaining or amusing as they are losers, can they accurately be right then when they say I am the one in the wrong always?? If this is one of my earliest memories and is followed by many more of an abusive nature, are these people trustworthy? I am very confused as people seem to like them all. I have no friends, have problems with social anxiety. I feel that in a couple of years I may end up dead or homeless. Are my family right? I have a first cl degree and working towards a masters. Do you think it is possible to cut ties with them and find good people in your life?They tell me that you can never rely on anyone or trust anyone but your family but they have made me feel horrible my whole life? Why do they tell me that when I am not safe in the first place? I wish they were dead. I despise and resent these *****.