Is it my Mars in Leo that's making me so rebellious?

I'm a Leo, and I get angry really quickly, especially because of my stupid cousin, (me and him are born in the same day 2 august, but i'm 1 year older then him serves him right) and we always fight. He likes it, he does it on purpose,m but I hate him,. and Because of this I don't think 2 Leo are compatible, and I think it's may be because of your Mars in Leo