I cannot tell the difference between right and wrong, why?

All my life I've been told I am wrong, about everything.

So in arguments/discussions with my boyfriend, friends, work mates etc. I have no back bone, I just keep my opinion to myself. Sometimes I try and show my interest and opinion but it spills out like I'm a dumbass.

It's almost like I've conditioned myself to come across as dumb when inside I'm actually quite wise and have been through many interesting experiences that I should share. I act shy, reserved with no opinions when inside I have many opinions and questions. I want to make friends, talk, be out-going and fun, that is my true self. I just can't crack this shell around me.

And most of all I wish I could stand up for myself and know when I'm actually in the wrong or right.

I am so confused.

You should keep negative opinions to yourself and ask questions always. You aren't dumb at all no matter who says you are.