This sounds a lot more like the problem than entitlement.
But nothing can be done about it. Getting professionals in the field to be more respectful of women? Can be done. Making efforts to reach out in elementary schools earlier and get girls more interested in tech at an early age? Sure. Great stuff. Getting teenaged boys to stop swaggering at each other, especially in front of the girls? Like stopping the tide from coming in. Never going to happen.
No sarcasm, no cynicism. You can't make teenage boys not be teenage boys. People have been trying for a long time for reasons a lot better and more numerous than this.
It may help to be less intimidated, though, to point out that while swaggering at each other, teenage boys can often be... shall we say... less than truthful? I've been programming since I was about nine... if by "programming" you mean stringing together some GOTOs and PRINTs in BASIC. I didn't really start programming programming until college. But rest assured teenage-boy me isn't exactly going to fill in the less-than-flattering details of my tech experience while claiming to have been programming since I was nine.
(Oh... and... don't try to throw this fact back in the teenaged boy's face. Whatever will happen, it won't be fun for anyone. Just keep it in the back of your head, share it as needed.)