Beginner having a lot of trouble learning node & express.

I'm 18 and I've been doing web design on & off for 2 1/2 years, with about 2 years of experience in javascript. Lately, I've been getting really into learning more and taking it seriously so I can go off to college and study more about web dev.

I understand javascript fairly well, and can make simple apps and add extra functionality to websites with what I know about the language. However, as I try to learn node, I can't find any tutorials that go in depth on just using node (learning the module system, events, buffers etc.) I'm not against using express, but I do wanna understand the core of node first at least to some degree, not just writing the same hello world server over and over then jumping into some other framework.

That being said, I've also looked at express tutorials, and they're all A. out of date or B. too complex. They'll use terms and talk about concepts that I just don't understand yet. Also, with everyone freaking out about mongodb recently, I'm having trouble finding any tutorials that use postgres or other alternatives. Are there any recommended places I can go to learn these 2 things (I don't mind if I have to pay either)? If I'm not understanding node/express just by looking at their docs, am I not smart enough yet to dive into these technologies? Thanks in advance for any help!