@ Author,
1. A mere engagement is not called as the social binding or final domestic contract.
2. Here it should be noted that any social or domestic agreement (an engagement a agreement for marriage in future) is not count under valid agreement or any contract which can be enforced by any law.
3. You have to be bold and frankly put your considerations out over her and parent's.
4. You have very less time so start soon and clear cut throw your point's what made you to call off your marriage.
5. If they are sensible person's then definately they will listen you and amicably bind up the future thought's.
6. It is a hell rather than heaven if marriage happen's against the will of either of the spouse.So,think ahead before joining such institution.
7. Every thing can be done prior to marriage but whatever done after that all have to be legaly done.
8. So,don't waste time get some gut's ,if not then have a hard rum or taquila engulf with all the pain's you would face in future if you will be married by her,then wash your face and spray some refresher inside your mouth and directly go to unveil your pain's to all and completely bind up all.......
best of luck.