It depends on how fast you can learn things. Almost all of us, at least know how to know turn on/off a DSLR. With regular and proper practice, you can learn to use a DSLR quickly. To get better guidance, you can also take classes. You can either attend online classes or go for offline classes. It usually takes up to 3 to 4 years to completely learn to use a DSLR camera. But if you are smart enough, then you can get done before that.