I've been doing it for 52 years (with a gap during the late 70s) and still teaching myself new things.
You let other people in the field say it. And that happens when it becomes accountable. For some it happens early in their career. For others, entire careers end and the words have never been said.
And I say this while thoroughly enjoying a quote by one of the comedy greats, George Carlin, where he was quoted a legendary cellist, Pablo Casals, who kept practicing daily into his 90s, saying "I'm beginning to notice some improvement".
Recognizing your skill while also recognizing (perhaps even immense) potential for improvement are not mutually exclusive.
I get that humility is a virtue, but at some point you have to admit that you're capable of doing a piece of work.
Humility is absolutely necessary in any skill development (and in general), but false humility - such as has been on display by various responses - is just as bad as the lack of it.
still feel like that lil kid. other ppls program humble me and teach me how little i know.
sure i understand more than i did when i started, but theres various reasons you're never 'there', and to me, i wonder if feeling you are good would even benefit you.
sure, you can still program C like in the 90s. Still write python like its on v2, or html and CSS like its 1999, but in reality to tap into the systems and their potential you need to constantly keep up. and i think its pretty much impossible to keep up with everything. there is so much, and more and more every day...
im a bad programmer. my bugs sometimes compute stuff!