At what point do you stop waiting to feel ready and just make a career change?

I've been a graphic designer for about seven years. I'm decent at it, get good feedback, and the work is steady. But for the past two years I've been quietly learning UX on the side. Courses, case studies, rebuilding my portfolio piece by piece. By most measures I'm probably ready to start applying. But I keep telling myself I need one more project, one more certificate, one more thing before I'm actually qualified enough to make the move.

I think I know what this is. It's fear dressed up as preparation.

The problem is I can't tell where genuine readiness ends and the fearbased stalling begins. I don't want to apply too early and embarrass myself in interviews. But I also know I could keep adding to my portfolio forever and never actually send anything.

For people who've successfully switched into a new role or field: how did you know you were actually ready versus just comfortable in the learning phase? Did something specific push you to finally apply? Or did you just force yourself to send the first application and figure it out from there?

Would love to hear from people who made a lateral or adjacent career shift and what finally got them moving.