(there's) no turning back (now)

expression The current course of action cannot be reversed or undone. A: "I know skydiving was my idea, but I don't think I can do this!" B: "Well, we're already up in the air—no turning back now!" A: "I'm really worried that the new product isn't going to succeed." B: "Well, there's no turning back, regardless of the outcome. We've sunk too much money into R&D and marketing not to release it now." A: "What am I going to do? I'm supposed to get married in the morning—there's no turning back now!" B: "OK, you're just feeling some pre-wedding panic. Let's sit down and take some deep breaths."