HAVE YOU EVER ASKED THIS QUESTION?
While it is true that the most important aspects of training jiu-jitsu are to enjoy yourself and improve your techniques, there is nothing wrong with wanting to progress to a higher belt.
So, set a goal to be a blue belt! (Or a higher belt!)
You will be far less likely to skip a training session and stay home on the couch when you know the only way you can reach your goal is to get your gi and get on the mat. The vision of that goal will exert a strong pull on you.
In other words: The time it takes to get a blue belt (or any higher belt) depends only on you and your commitment!
You can also apply this to your everyday life: setting short-term goals, medium-term goals and long-term goals will help you grow, evolve and conquer everything you have ever wanted!