Any advice on learning your true worth? Assume for a minute that Glassdoor is useless, as the "salary range" it displays shows that the maximum is 2-2.5x the minimum.
There is no "true worth" that you can look up on a website. Your salary is your cost in the labor market. And like any market, worth is determined by what people are willing to pay. Go out and interview, get some offer sand see who is willing to compete for you. That's how you get your true worth.
The only thing that matter is what they think you can get elsewhere. eg. what others are willing to pay. Think of it as an auction. Something might be worth $100 but if the highest bid is $10 you are only going to bid $15 not $100.