You're right - up to a point; we're all shaped to some extent by our families and other childhood experiences. This is one reason why the Bible urges parents to be wise in raising their children. It says, "Train a child in the way he should go, and when he is old he will not turn from it" (Proverbs 22:6).
But we alone are responsible for our actions - and when we refuse to face up to our failures or turn from sinful ways, we are wrong. Take, for example, someone who grew up with parents who were constantly angry, or even violent. Does that give him or her the right to be angry and violent also? No, of course not. We must be honest about our shortcomings and failures - and then seek (with God's help) to change them.
And this is one reason why we need Christ. Only He can help us overcome the wrong habits we grew up with, and only He can take away the scars of the past and change our hearts. The Bible says, "I will give you a new heart and put a new spirit in you; I will remove from you your heart of stone" (Ezekiel 36:26). This is what we all need - and it is possible, because God loves us and has the power to change our lives.
But we need Christ for another reason: to forgive us when we do sin. Don't excuse your sinful ways, but turn to Christ for the forgiveness and help you need.