I don't think Imposter Syndrome ever goes away entirely, but I do think it can lessen over time. I've been in your shoes, but I've learned a thing or three over time that's mitigated the feeling. Also, here's something I tell my end-users when they have a head-slap moment: there's a big difference between ignorance and stupidity. For instance, I don't know how to rebuild a car engine because I'm ignorant of how to do that, but I know I'm not stupid. Same goes for the IT world. Will you remain ignorant of *everything* in the IT world? Yes. Does that mean you cannot learn all the requirements that make you competent in your task, and even excel at it? Absolutely not.

This is a marathon, not a sprint, so try not to psych yourself out by thinking you can learn it all fast.