I would never have come to believe it was true, but going forward I realized you do not need to know everything from before. Some things are just meant to be figured out and it's okay to say “Yes” even if you do not know everything about how it will be done.
While I was in college I used to freelance a lot and do a lot of projects. Trust me, most of the projects I said yes to were something I never had heard of before. That has helped me in learning so much that I wouldn’t have, had I not said yes. Sometimes it’s just about taking that extra step.
In a hindsight, I came to believe and even now that there is a difference between what you can do and what you are not familiar with but can do it if you do your homework.
As a developer, if you wait for an opportunity to adapt to your expectations, you will never test your boundaries.
There might be a case you might not be able to deliver it completely but I’m sure that is better than not attempting it at first.