One the most important times during your lift is when you approach the bar. It doesn’t matter what the lift is, it could a deadlift, squat, snatch etc. When you approach the bar is when the lift really starts, not when you start moving the weight.
If your eyes are looking at the bar thinking the lift is going to be heavy the weight has already defeated you. Being nervous is OK, it shows that you care but you never want nerves to turn into fear.
The bar is a dead object in space. It has NO control over you, you control yourself. Your mind tells your body/ muscles to take action to move the bar.
Confidence comes from your heart, which links the mind and the body. Find you confidence in your approach, in the gym and outside the gym!