Sale of property belonging to you during your minority is no doubt invalid and illegal, however you should have made a claim about this within three years from the date of attaining majority.

Now since you have lost a chance you can have a equal share in the residual property.

However you may consult a local lawyer who will suggest your some other idea to retrieve the lost property or to put pressure on your sister to forego her share due to the previous transaction that took place during your minority.

De Facto guardian cannot sell the property on behalf of the minor owner. Only the natural guardian or the court appointed guardian can sell the property belonging to minor or involving minor interest. However though you were a minor by age that time, you have also put your signature in it, it means that you are aware of the sale that time itself, but chose not to claim even after three years after attaining majority. The question is not about defacto guardian selling the property, it is about the minor' property sold without following the legal procedure. The sale by defacto guardian is absolutely null and void but that should have been made within three years from the date f such knowledge. You cannot say that you never had the knowledge about it either then or subsequently.So what is your legal position and than decide about further legal action on it.

I told you to consult a local lawyer who will be having more clues which cant be stated in open in such public forums like these.

1) it is necessary to peruse the registered document cited by you to advice

2) the property was sold for your sister marriage ie for necessity

3) for sale of minor share court consent is necessary

4) within 3 years of attaining majority you can challenge the sale of your age was wrongly shown

1) You were only 15 at the time of sale

2) your consent was not valid consent

3) but since period of 3 years has elapsed since you attained majority your claim would be barred by limitation

1. In accordance with the document of transfer executed by your grandfather you and your sister were to get an equal share in the 5 acres land. Both of you became the co owners of the land as soon as the document was executed. Your mother's assertion of having a share in the land is not supported by the law.

2. The land owned by you could not have been sold by your parents except with a court order. You can challenge the sale made by your parents. The time limit to challenge the sale is 3 and not 12 years.

3. You and your sister have an equal share in the remaining 3.5 acres of land.