It doesn't matter if what you are carrying is legal or not. What matters is how you use what you have. A pillow isn't something you would think of as a weapon but if used to suffocate someone it will be seen as such by the courts. I wasn't trying to encourage anyone to use a pen as a weapon, what needs to be done is get familiar with your local laws. This way you know what you are legally able to do in self defense. Many states have different views on what "reasonable force" is. In some states it's legal to use deadly force to eject an intruder from your home but in many it will land you in prison, regardless of what you used to execute your actions. What is considered excessive force in your state? What are the justifications for deadly force in your state and how are those justifications defined? In some states you are justified in defending your self if someone verbally threatens you and shows physical intent to carry out the threat (shoving, poking a finger in your chest or other aggressive physical actions but not necessarily striking). In other states they must physically attack you first. Know what your legal actions are before you start carrying ANYTHING with the intent of using it for self defense.
Enjoy life while you can, you never know when things will change.