Another way to look at this is to think how much you’d regret not asking out your crush. This can help you to realize how much this matters to you and how important it is to at least try.
Prepare ahead what you want to say, so that you don’t feel confused or at a loss for words. Visualize asking out your crush and responding to the different possible ways that your crush might respond, so that you may take their answer with grace. For help on knowing how to ask out your crush, see How to Ask Out Your Crush.