Birth control: should I take it?

Quick question for you ladies, I am in my early twenties and have a boyfriend for about a year now. We don't see eachother too often but when we do we are sexually active, no protection is used. I've been going back and forth about taking some type of birth control. Honestly I don't want to because I don't want to mess with my weight, I don't want a substance interfering with my hormones and possibly interfere with my fertility the one day I do decide to have a child. I know that birth control can change you and I am against that.  Just my opinion, let me know what you ladies think. :) Thanks.