The spirit soul does not evolve like the body. The body has got six transformations, namely, the body takes its birth, it grows, it remains for some time, it produces some by-products and it dwindles and then it vanishes. All these six changes of the body are not applicable to the soul. The soul is permanent. It has no development, no decrease, no destruction, nothing of the sort as compared with the body. The only difficulty of the soul is that in the conditioned state of material body, the soul is supposed to forget its identity; by chanting Hare Krishna gradually the soul revives its identity or it comes out from the forgetfulness. This is not exactly development, but it is reviving one's consciousness. Everything will be gradually clear as you go on chanting Hare Krishna. Please try to chant at least 16 rounds of the beads and while chanting try to hear each and every word. That will make you advance in every respect.
If you analyze yourself very scrutinizingly then you will find that you are spirit soul. How can you do it if you think of yourself, what you are, you will analyze that you are not this body, you are not this hand, you are not this leg, you are not this mouth, but you are something. And what is that something? That something is continuing. When you were a child that something was there, when you were a little more, a girl, then that same something was there and now you are a young girl,, the same something is there, and when you will be old enough, the same something is there. Therefore, this same something is there even you have changed your body in so many ways. Therefore next conclusion should be that even if you change to another body, that something will continue. Therefore that something will continue. All this truth about the soul will gradually develop as you go on chanting Hare Krishna.