Hey! Don't be embarrassed. It's just an overflow of emotion, hormones, and natural responses. So what? You find her attractive. That's a good thing, right. If she mentions it, laugh it off and if she has a problem with it, she's not ready to date.

Best of luck.

Didn't I respond to this on another forum?

You're a guy. It happens. It's nothing to be ashamed of or embarrassed about. If she's bothered by a guy with an erection, then she's too immature to be dating. You can try wearing jockeys instead of boxers, but otherwise... don't worry about it.