Buddhism and Karma??????????

I'm a new buddhist although I've belived init more than my birth religion christian its the first religion ive actually wanted to learn about and wanted to be a part of.. However, in the past I made many bad choices as a teenager.. burglar(high school), bully(elementary school) sure enough i was a good little kid at first and had a nice life with friends an deverything.. when i turned bad bad thigns started to happen..then it got me thinking maybe my past lifes are also to blaim or maybe its just this life.. you see i moved to this country from Russia(USA) and growing up i was always different outcast etc.. which probably shaped teh person i was.. dont get me wrong i am actually a ncie person like ill help someone in need save a kid being beaten up anything i can.. im actualy a better person now.. than i was before.. how will this affect me in my future lives?