Double Standard Dress Code

Apparently at my place of work the rule isn't "No Jeans" its just Anna can't wear jeans. I understand no blue jeans and when I first started there I didn't wear any jeans period. But then I noticed some coworkers were wearing gray or black jeans. They were wearing them often enough (and no not just on Saturdays when blue jeans are okay) so I started wearing my gray jeans.

Yesterday, I walk in late I'm frazzled because i hate being late but I just lost track of time and had the I-have-nothing-to-wear syndrome. I'm wearing my gray jeans and the first thing my boss says to me is "Oh you can't wear jeans." I was like okay whatever. A little later she comes over to explain it to me more (because thats what she always does even though I got it the first time). She tells me we can't wear jeans except on Saturdays because we have to be business casual to match our customers. I just keep working and try to block her out. Later I notice her daughter, who has a higher position in the company than I do, wearing black jeans. And yes she wears black jeans almost everyday and never works on Saturday, which is the only jeans are okay day. Not to mention my coworker that I got the idea from since her jeans are a very faded black. Oh and let me not forget the owners son who was wearing BLUE jeans. I've come to the conclusion that the rule only applies to me. If I get a talking to ever again about my dress code violations then I'm just might have to point all these things out. I don't like being a tattle tale but I think it's bull crap that everyone else can wear their black or gray jeans except for me just because I'm not related to the owners or have worked there for years.