I’ve come close to Zina, but barely managed to restrain myself. I’ve become attached to a woman and it’s hard to be patient as I cannot marry her awhile. So, can I get a nikkah done with the imam as her wali without knowledge of her parents, because we fear Zina?

"Why not with her wali? This is not allowed — may Allah reward you — unless her wali is making ʿaḍl of her. Also, please wake up and stop getting attached to women like this, as it may ruin your religion. Don't you want barakah from Allah? How can you attain barakah when you're so deep in sin? And if there's no barakah from Allah, do you really think you'll have a happy life even if she becomes your wife? Abandon this haram relationship immediately, turn to Allah, and make duʿāʾ that He gives you what is best for your dīn, your dunyā, and your hereafter."