So wait, where are you going to be training? Because if your answer is "nowhere, training by myself" then you will not be prepared for either sport, self defense, or MMA situations. You need a real instructor and real training partners.
Furthermore if you wait until blue belt to compete, you'll be at a disadvantage compared to those who started competing at white belt.
Last thing, whether you're training "BJJ" or "SJJ" or "GJJ" or whatever, you're training the same martial art. Don't buy into all the stuff from the Torrance Academy branch of the Gracie family. Rener and Ryron are excellent instructors and practitioners, but there is a lot of propaganda and salesmanship mixed into what they're saying as well.
I used to think like that too man, thing is, as far as I progress in bjj, I feel like its getting more and more towards the sportive side, when I go to class and ask my instructor to put on some gloves and do some mma sort of training, he is like... nothing... I only get to do that on saturdays on no gi days, and its more MMA than anything (this means starting standing and fucking around for like 3 minutes thrwoing horrible punches and horrible some sort of kicks, because most of the guys doing that dont train stand up, so its like, wtf is the point of doing this? why am I wasting my time doing something I dont know nor I train for?), then I came out and say, dude im not into MMA, im into getting my jiu jitsu to work on real life, then he goes, ohh you are just a pussy ass that want to do half ass things, then I go, NO, I want to train jiu jitsu, not MMA, I dont give a rat ass fuck about the stand up part, I dont want to be learining how to throw a punch or a kick on a MMA class, I want to train jiu jitsu for real life. Then the circle goes back again (it doesnt help that those instructors are also training MT), so what I do, ok lets train MMA, we start and I sit on my but or pull guard... then the rant starts, OHH HOW THE FUCK ARE YOU GOING TO DO THAT... to my simple explanation. I WANT TO TRAIN JIU JITSU, I WANT TO TRAIN MY GUARD WITH PUNCHES, not play half ass MT (wich I dont know squad about, nor am interesting in practicing)... Im not training for MMA, im trainign my jiu jistu for SD, and in a SD situation, Im pretty sure if I lay on top, I can fuck up pretty much any untrained person upto 100k no problem (im alson pretty sure my halfass bahina wil be more than enough to take most untrained peole to the ground) , shit hits the fan if I got taken down and have someone on top of me raining puches.. that is what I want to train for...