i have nothing, no ammo, no clothe, no potions. just a movable character
I've done a no-shots-fired (until the boss fight) virgin run. And by virgin I mean not even getting grabbed (scripted mandatory scenes don't count, as they don't give sex EXP anyway).
It won't be easy, but you can do it. I believe in you! lol
Edit: Also don't worry about no ammo before the boss. You'll have a technically unlimited supply.