To start off with, resorting to honest physical violence to solve a problem is barbaric and immature, and I'd never employ it in anything other than a defensive capacity. That said, I go by a weight and build rule when it comes to women. I'll respond with an equal amount of force as I would for a man of the same size weight and build.
Example: OP is 5'7" and 112 lbs. I'm the same height but outweigh him by about 50 lbs, and that's from a fair few hours at the gym. I think most people would agree that (barring any of the self defense training either of us may have had) if he attacked, I could probably restrain him, or otherwise resolve the conflict without excessive force. Bingo, we both walk away with much less in the way of injuries than if I where to have simply retaliated with every last ounce of strength and brutality I'm capable of. Sounds like a good way to de-escalate a situation, no? Well, a few months that exact situation happened to me, except that it was a girl that was the same height weight and build as OP (no offense intended, OP, but it fits the example). Now, had she, or a guy, been equal to me in strength and size, most certainly would have responded with a lot more force than I would have with this girl, or OP, and I would do so regardless of gender.
Long story short: Don't be a brute, know your strength, how to control it, and how to respond to a violent situation with appropriate force. If you can do that you'll be just fine. Gender won't really matter, and if it does, the complaining party is probably not worth very much.
P.S. For what it's worth OP, if a girl proportionally sized to me as your sister was to you blocked my path and wouldn't let me pass after repeated attempts to do so without a physical altercation, I'd probably shove her out of the way too.
Whew, looong first post, sorry for the wall-o-text people, and congrats if you got through the whole thing.