I am upset that people get so much wrong about me.
What are people assuming that is wrong about you?
I know that most people don't guess my age correctly.
If you feel it is such a heavy weight you should be open to people you can trust. If you don't share information with other people how you they be aware of your age?
I'm not going to tell everyone my age because I am afraid they will judge me.
Don't worry so much about what others think. Share with others the information you are comfortable with and they will share back. Eventually you'll wonder why you were so worried about your age in the first place.