I hate losing to people whose character level is 0 and player level is 0 and yet they know how to play so much better. Makes me feel like such trash.
You shouldn't let this bother you. Online rank has literally nothing to do with the experience or skill level of the player.
Some of us have been competing for 15 to 20 years in these things, and many people put a hundred hours into the betas and pre-release builds at shows already.
Just like in a real life tournament, you should treat every opponent as a mystery. There is no number on any screen anywhere that can tell you if JoeShmoe82 is brand new to fighting games, or the alt account of a 10 year veteran.
Just keep fighting and learning.