Accepting the label of ‘Narcissist’ to describe yourself is probably not a good idea and is somewhat compartmentalising in terms of a character description. It can also be a comforting excuse to be able to ascribe certain of your behaviours to a ‘condition’.
It might be better for you to embrace these feelings that you have as worthy, to a degree.
Everyone needs to have a healthy degree of self appreciation. We would neglect ourselves otherwise.
Having read your other question on this subject, I suspect that your problem lies in your need for attention from others (also not a bad thing as such,except when taken to extremes), possibly stemming from an underlying sense of low self esteem.
“I’m always thinking of the people around me…and who matters and who doesn’t and who I need to be nice to and who better remember their place around me.” This sentence alone, from the ‘detail’ section of your previous Q is very telling about your general perspective on the world that you inhabit. You seem to think that you are in mortal competition with others (which you need not), that you are in a social hierarchy ( which might just be your imagining) and that there is a pecking order governing how civilly you treat people and expect to be treated yourself.
Perhaps a slight shift in attitude will be of help to you. If you adopt the attitude that you “need” to be nice to everyone ( Its nice to be nice ), then you will have one less worry. I suspect that you will be more highly thought of as a consequence.
If you adopt the attitude that all people are of equal worth, then you won,t have to worry about being “the most important person in the room”. All the good things about you won’t be diminished if you do this. They may well be enhanced.
You could also adopt the attitude that everyone (including you) deserves at least common courtesy and deserves to be treated with respect.
Finally, its ok to feel good about yourself and your attributes and achievements. Allow yourself to and don’t think that you should have to feel bad about it. But remember to be kind and considerate to others. You’ll find that you will get the same back.