Part of the screening that helps me look at someone with lessor experience is if what they were doing closely matches the position details then I am likely to set them up for a chat, even with the difference in experience. I look at it this way, someone who has 5+ years of web dev experience in other industries and someone who has 3 years in our specific industry are nearly equivalent in many ways. One might require less technical help, but need more industry help and vice-versa so kinda a wash in many ways. This isn't always true of course, but is a good generalization.
"I don't have the standard number of years, but I have worked in other industries which add value in design decisions."
"I don't have the standard number of years, but I am am competent and hungry to go to the next level"
"I don't have the standard number of years, but I..."
If you feel imposter syndrome, that is normal. There will always be things to learn, and frankly learning on the job is the best.
Good luck!
Also, a lot of job descriptions are of the "perfect" candidate, i.e. the person hired may not satisfy each of the requirements, especially years of experience.
With that said, every position is different. Maybe the hiring manager has bad luck hiring candidates with fewer years of experience than he/she thought was required, and maybe they won't budge. Doesn't hurt to try!
- don't bring it up on your own
- tell the truth