All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
There is no doubt that parents' consent is not a condition in the marriage validity. In other words, your marriage is valid even though your parents do not give their approval since Allaah, The Great and Almighty, granted a sane man the full authority concerning marriage, selling, purchasing and all other daily transactions. Thus, if you don't have your parents' consent in such above matters, then this does not constitute any form of ingratitude, because Islamically, you have the right to do so. But, it is better to seek your parents' advice concerning your marriage. This advice, without a doubt, pleases them since your marriage is a family issue that they are more deserving to take part in.
Thereupon, since conditions of marriage such as a guardian of woman and witnesses and the absence of any impediment are all met, then you are not obliged to inform you parents, especially if you fear of committing some Prohibited actions. We advise you to accomplish such a contract and may Allaah bless you.
Allaah Knows best.