Hi there,
I want you to consider the situation very carefully right now. You are legally old enough to pursue a relationship with someone who is 34 years old, however, your teacher is in a position of responsibility. I'm not sure how that stands where you live, but it's illegal over here to have any sort of relationship with a teacher, other than a purely professional one. As a teacher, she ought to be thoroughly informed on what is appropriate and what is not. By anyone's standards, her behaviour is far from acceptable, and in acting as she is, she runs the risk of permanently damaging her career as well as getting in trouble with the law. Disregarding this, you must also remember that she is over ten years older than you, married and has a family. These factors alone should be large enough warning signs to tell you to steer clear. Let us assume that she really likes you and is prepared to give up her career and personal life to pursue a relationship with you. The very fact that she would do this indicates that she would probably turn around and do the same thing to you if she felt someone better came along. As to why she is doing this, it may simply be that her own personal life is unsatisfactory, though I wouldn't look into it any further than that.
It does indeed sound like you are enjoying her attentions, but this puts you just as much in the wrong as she. Tell her plainly that it has to stop.