No, not generally. As long as your belt is white and you tell people that you're new, you should be fine.
I'm starting BJJ within the next few weeks and was searching online for a gi. Does the color of the gi itself (not the belt obviously) have any significance? In other words, if I show up as a newbie in a red or blue gi, does that mean something? Or should I just buy a white one. Also, what about patches? Basicaly, I just want to know if it's offensive or just a bad idea to show up in anything other than a plain white gi. Thanks!
This is actually true. I personally stick to white gi's because that makes it easier for me (I don't have to worry about grabbing the wrong gi pants in the dark and looking ridiculous at a competition or demo).
I wouldn't recommend a red gi, since they are not allowed in tournaments. You are allowed to wear white, blue, or black in tournaments.
Still, if you want to wear a red gi, it's all a matter of personal preference. Hermes Franca and a bunch of other experienced guys do, but, as mentioned, it's usually not a good starter gi because it's not allowed in tournaments.
This has never been a problem at my gym. I can see why it would be, as the colored gis usually show some experience and commitment to the style, but I've never seen this come up.
Buy a white one, or a blue one, not any other colors. Wearing a red or black Gi is like wearing a target around your neck pretty much, even blue ones to an extent
That said, it's probably an issue of where you train more than anything. You may want to check with your instructor, and not with the guys on the internet who don't know the specific environment your stepping into.
BJJ is a diverse world, and so alot of this stuff really is school-specific, just like the style of jiu-jitsu is school-specific. All we can offer you is insight into our own experiences and, as helpful as that might be, yours is probably going to be different.