Top or Bottom?

I am new to the whole community and am interested in a girl that is a self proclaimed top. She dresses kinda girly and I would describe her as the skater punk type. Me on the other hand am more of the boi type, wear guys clothes, have a faux-hawk, etc. I guess I could be described as a top or a versitle top but what I was wondering is what exactly does that mean? Just that she is more aggressive in bed or that she gets and doesn't receive? Any help/advice would be appreciated. Thanks!!