Is it normal to not know who you are?

I dont know 'who' I am. i just noticed that everything i identify with is so fleeting and is subject to change at literally any time. my flesh body, my name, appearance, age, beliefs, opinions, personality, voice, abilities, attitude. is there really anything about "me" that isnt prone to change. do these things even make me "me" if they can just change anyway. when I say someone is something that's assuming that that is a stable label that I can identify them by that wont ever change...but is it really? quick change of environment and suddenly they become a new person. idk I just see that too much. so many people say that they wouldn't have turned out the way someone else did because they would have reacted or done differently but I mean you cant really say that can you? you didnt experience every second of life through their shoes. you're just kind of projecting your own arbitrary collection of experiences and applying it to the situation. so yeah of course you're going to say you would do differently. but who knows what you would have done if you grew up and witnessed all the things they did. you cant use that argument to support the claim. I mean that's why theres stereotypes right. poor people stereotypes, rich people stereotypes, ghetto people, upper middle class people, people who grew up in an abusive house hold, those who grew up in nice ones. none of these people seem to stay from the patterns of the product produced from these kinds of environments. ok this got long but yeah is contemplating any of this normal for any of you?