learn how to knock

I understand your point. Knocking is a sign of courtesy to the person in the room to inform the occupant of his or her intention to come in. I guess your mom still considers you the little daughter that she has that she can just barge in your room any time of the day.

No you’re not too sensitive. My son is 16 and the only rule in our house is for him to never lock his door when sleeping. But whenever we go to his room, we either knock or i shout before. Entering his room. The reason why we don’t allow him to lock his room is that he sleeps like a log and very hard to wake him up.

No, it's best if the door is locked so that people don't enter without permission.

My mom would do that too. I prefer if someone knock first. I might not be dressing appropriately at the time.

yes that is just common courtesy for me

No! Everyone needs privacy. One time, I am changing my clothes and my dad just barged in without knocking I really got irritated and told them that I need a lock. Hahahaha.

It is best to give a warning since you never know who is coming to your home.

you're not too sensitive, people should knock before coming in.