How can i stop being so arrogant?

I am a 15 year old male. Being so, my age can be a factor for it, maybe it's normal? What I am able to brag about, is my intelligence. I am very smart, almost a genius. I am able to recognize many everyday "patterns", sequences, ironies, and even able to detect almost everybody's lies. My attitude is not like this, I like to be charismatic, helpful, selfless, and even try to appeal humbleness, but, from the inside, I am very arrogant. Every time I manage to think of or notice a logical pattern or behaviour, I am unable to ignore myself and say "How brilliant I am, only I am able to do such things". Even though I try to be humble, my mind does not agree with me, it's like a contradiction. I don't really mind my problem, it's just that is distracts me from thinking straight and logically sometimes. I am also a liar, and a pretty good one. Every time I get into an unexpected argument or conflict, I am able to get away with it, harmless. But please, try to believe that all that I am mentioning in here is truth, I just want an advice. If you meet me, you would not think of me as an"intellectual person", because I have a sense of humour, and smile. I know this question is very....tentative, but whatever!

Thank you very much!