I've been winning games but it still says 190 until brown belt, even after playing with people in my skill level.

Your rank is based on ELO which you gain by beating people considered "better" then you and you are just playing people your belt and rank and maybe even people considered "worse" then you which gives to ELO gain.

Its not rank its belt. It counts how many games you played (this is QI ) and needs an amount to jump to other belt. you've played 310 games till now (310 QI yayy). and brown belt needs 500 games.

The belt is for Belt Restricted rooms and QI restricted items. Most people says;
"Belt does not matter, its about skill" just calm down and level up with most exprience.