你应该纵向比较(打了一半中文,一个back键就毁了. so bear with english)
Even since young, we have been constantly comparing ourselves (or been compared) with our peers. But honestly, 人是不平等的,除了我们的灵魂和生命以外。Timing, opportunities, network etc. all hugely affect your career achievement, and your salary. Put an good example, in last decade, beginning salary for IT fresh undergraduate changed from 3000 around to 2000 or below, then back to 3000. But i don't think the average quality of those students change that much every year!
I think you should not compare you or your pay to ppl in same age (though it’s seems a very simple and intuitively way). This peer comparison only gives you a relatively mark but nothing more (like an very innaccurate GPS, some information, but don't rely on it). It’s probably better or more objective to compare with the same you 2 years ago or 4-5 years ago.
Think another way of the same current pay number. if one start with 2000+ and double your pay in last 5 years (more...)