Hey dont be so hard on yourself, its not a phase as what @echizen had said. However, i have read from somewhere that women are bicurious in nature. So, yeah maybe that's the reason why you have imaginations of making out with a girl. Kinky activities is however different, it could be your subconscious desires, which may come true given the right person to do it with. :)
yeah, enjoy life - do not be limited by cultures. :)