Having sex with my girlfriend for the first time. How to find the entrance quickly? How can we not be nervous and avoid "handing in the gun" in advance?

Foreplay is very important. Don't focus on your girlfriend, divert your attention. The more nervous, the easier it is to end early. You should either wear a condom or avoid too much friction and irritation. When I first started doing it, the first few times were basically over. You should have an adaptation process and get better slowly. The gun is getting brighter and brighter!