I'm confused about whether I'm in school uniform tomorrow or not?

Reasons why I'm confused:

-My brother is in non-school uniform and he goes to my school. However, there have been a couple of occasions where I have had non-school uniform and he hasn't, and vice versa.

-One friend said it is, but another 2 have said that it isn't. Another friend asked me about it, but this was first time I even heard about it, so I said no.

-It says it is on my school's website, however no teacher has mentioned it.

-I asked the question on Facebook, to which one person said yes and one said no (you know what it's like, friends confusing you and trying to convince you the wrong way)

If you had this information, what would you do? Thanks in advance