Yes of course, you bring flexibility by practicing Yoga. From my point of view Yoga is even the best way to make yourself flexible, because it works very smoothly and gently with your body. For example if you perform butterfly posture, it is no matter how close your ankles goe to your perineum and how close your knees reach to the floor. No matter at what point you start it will be helpful for your hips and back, and regular practice will bring more flexibility. Don't avoid Yoga just because you think you aren't flexible. In fact, if you have tight muscles, yoga is just the thing to loosen you up. The point of Yoga is not to show off how flexible you are, but rather to become more flexible over time while enjoying Yoga's health benefits. Yoga is not like gymnastics, in which the most flexible person gets a medal. It is a personal practice, infinitely adaptable to fit your needs. To bring you in balance, Yoga brings balance into your life. Flexibility is just a very small part of balance.