No matter how nervous you feel, or how hot she looks, or how many people are watching, you have to approach.
Unless you approach her, you will never get to know her, befriend her, date her or have sex with her.
What’s the worst thing that could happen if you approach? She might turn you down. So what? It won’t kill  you. In fact, it will make you bolder, and you will find it easier to approach the next girl.
But if you don’t approach…you will almost certainly regret it…probably for the rest of your life.
When I talk to my clients, every one of them has a story about a girl they wanted to approach, but did not. And they still regret it today, years later.
The pain of being rejected by a woman is less (much less) than the pain of regret. So be a man and approach.