I have a mental block with this. I don’t know if I’m ready to create what a customer might want. What happens if I can’t deliver? How do you estimate well? Do

I have a mental block with this. I don’t know if I’m ready to create what a customer might want. What happens if I can’t deliver? How do you estimate well? Do people on Upwork expect that hiring someone there could be great or could be iffy? I guess I have a confidence issue with putting myself out there.