The problem with using software to critique your playing, especially with classical guitar, is that playing the correct notes is only a small part of the whole. For the beginner classical guitarist, learning a good technique (right and left hand positions and motions, correct sitting position, etc.) is much more important in the long term.
Having said that, it is certainly possible to use software to rate your ability to play the correct notes in the correct time. In the long run, though, you will likely find that the scoring that software will give you can be misleading because it does not take tone or timbre into account, only pitch.
For example, you can play A - 440 Hz on 4 different strings. In each case, the pitch is the same, but the note will sound very different if you play it on the 1st string, 5th fret as compared to the 4th string, 19th fret.
I am not aware of any software that can make that distinction. What can make the distinction, though, is the human ear. With a little bit of practice and deliberate listening, issues such as sudden shifts in timbre, or nail clicks (a common problem with classical guitar) will practically jump out at you.
In addition, part of the beauty of classical guitar is in the interpretation of the performer. Guitarists do not play the same piece the same way. If they did, there would be little point to having many guitarists. An important part of an artists interpretation is the rhythmic aspect. I am not familiar with all the software out there, but I have not heard of any software that gives the performer rhythmic flexibility while still accurately rating pitch throughout the piece.
Based on all of this, I would say the best judge of your playing at any level (outside of a professional teacher) is yourself. Record your practice sessions and listen to what you did. Try to keep specific goals in mind and focus on them so you do not get too side-tracked with any other issues you may hear, although keeping a note of them can be useful as well. Once you are comfortable with your recording, let a more experienced guitarist listen and critique it as well. This may help you notice things you otherwise would not have.