Sorry, but you can :D
I think there is usually a genetic factor which can emerge at any time. However, I think certain diseases- like eating disorders- can affect anyone.
could be either one.<br />
What do you think is wrong with you?<br />
you can message me the answer if you want.
develop but there are factors from birth
It depends. Some mental illnesses are the result of birth defects and others develop as a result of chemical imbalances and traumatic experiences.