I am 18, and I am a Catholic. I committed a huge sin. I lost my virginity. I met this person few days back, and he always asked me to have sex with him, but I always said no. I don't know how I ended up saying yes. I don't know what tempted me to say yes, even when I knew the consequences. Even he is a Catholic, but he doesn't care about religion and sins.
After this happened, he went back home, and I started feeling guilty. I regret what I have done. I have broken God's rules. I tried talking to him, but he didn't seem to be interested in it.
I can't tell my parents about it. I made the biggest mistake in my life. I am not worthy of getting married in the future. I am scared that if I get married, my sin may affect my marriage and also my kids. I am completely broken, and I don't know what should I do. I don't know if my sin can be forgiven because I did this even when I knew the consequences.
Yes, you've sinned, but it isn't the end of the world. You found out the hard way that God meant it when He said, "Now then, my sons, listen to me and do not depart from the words of my mouth. Keep your way far from her and do not go near the door of her house" (Proverbs 5:7-8). Just reverse it from "her" to "his" and it still applies. You said you don't know why you gave in, but the honest truth is that you didn't send him packing when he first mentioned wanting to have sex with you. Because you kept him around, he assumed your "no" was actually a "not yet."
As you now know, a claim of being religious doesn't mean a person actually is religious. In the Bible it is called being hypocritical (putting on an act). "Or do you not know that the unrighteous will not inherit the kingdom of God? Do not be deceived; neither fornicators, nor idolaters, nor adulterers, nor effeminate, nor homosexuals, nor thieves, nor the covetous, nor drunkards, nor revilers, nor swindlers, will inherit the kingdom of God. Such were some of you; but you were washed, but you were sanctified, but you were justified in the name of the Lord Jesus Christ and in the Spirit of our God" (I Corinthians 6:9-11). Notice that in Corinth there were former fornicators in the church; thus, it is possible for fornication to be forgiven. See also: Are You Unforgivable?
When a person leaves their sin and lives by God's laws, He doesn't hold the past against the person. Sins do have consequences and you might have some issues to overcome because you remember your sins, but that won't be God punishing you.
"Not that I have already obtained it or have already become perfect, but I press on so that I may lay hold of that for which also I was laid hold of by Christ Jesus. Brethren, I do not regard myself as having laid hold of it yet; but one thing I do: forgetting what lies behind and reaching forward to what lies ahead, I press on toward the goal for the prize of the upward call of God in Christ Jesus" (Philippians 3:12-14).
And if you haven't figured it out, dump the bum who used you for his pleasure. Find a good man and don't compromise your morals.