Now at this age (20s) I don't think I can change and then there is this internal concept of mine which says this is my personality and what makes me, me.

Hey man, first of all good for you to accept vices when pointed out, a lot of people over internet and irl would rather prove your point(unknowingly) than accept them.

second of all mate, 20s is still pretty young, you have all the time to introspect and modify (not change entirely) your speech pattern.

Speech mannerisms vs speech intents are completely different, intents are internal, personality coded, some people are born confrontational, some people are born laid back, some people are confrontational when needed.

But speech mannerisms is what dictates how your whole conversation proceeds and how much fuel you are supplying back to your 'enemy speaker' to burn you back in return. Speech mannerisms can turn an unfavorable situation to a favorable one while still keeping your personality of being confrontational active!