We pursue wisdom as a lifelong process of self cultivation. To commit to this insight path is to commit to greatness. As for how long it takes, it depends on what you commit. As a rule of thumb, three good practice sessions per week will enable reasonable progress. If you can only get two sessions in, you will maintain your level, but slip over time. Four sessions is best. So much depends on how you define 'Proficiency'. I seek to help you change your condition.
When refining and softening the body, progress can be easily measured in terms of range of movement, pain relief and raised energy levels. Structural accomplishment is similarly easy to quantify. You are clearly stronger.
Measuring mental development is not so simple. I have spent decades developing a method to train the mind in such a way that you know exactly what the training gets you and why it is important to get it. This training progression is transformational by design.
"You do the training and it does you."
That having been said, a reasonable level of physical integration can be reached in three years of dilligent practice. You will notice immediately more relaxation and increased energy. Going beyond this, it's hard to say how long it will take since students are so different and have such wildly different expectations. Besides, it's the journey, not the destination. Try to manage your expectations. This is one important aspect of "Empty Cup, Beginners' Mind".