Premarital sex is not a new concept, no matter how much people like to pretend it is. You can trace scripture and historical texts back thousands of year to see that lust and fornication have been a problem since… well, since we humans have been problems.
They tell you in sex ed that sex causes you to form a bond with someone. They throw some big chemical names at you that are apparently in your body and cause that emotional attachment to happen, then you move on (or back to) how important condoms are and why STDs are so scary.
As a middle schooler or teenager, you can't understand what it means to become permanently connected to someone as a result of a quick, physical act.
If you haven't even had your first kiss, you really can't imagine what it's like to develop such a complex and intimate connection with someone because you have yet to feel the butterflies in your stomach from a kiss. So you really don't know what it's like to have a whole different type of feeling in your stomach.
You never forget your first love. It's one of the most cliche things you consistently hear, but it's true. Ask anyone. I guarantee your parents can still spurt out their first love's name in a few seconds. And most people never forget their first time. I know all my friends can recount that often awkward and slightly terrifying moment as if it happened an hour ago. When you mix those two, especially if you are in your teens, oh boy.
You never forget that. No matter how hard you try.
Everything you hear about sex is true: it's amazing, fantastic, life-changing, etc. There's a reason people have done it as frequently as they do, for as long as they have. But every time you sleep with someone, you leave a piece of yourself with them. Every time you choose to take that final physical step with someone, you cannot go back and collect that piece of your dignity and soul that you left with someone.
So, imagine what happens when you break up with someone you've slept with. Or that you just hooked up with. You have given someone a little slice of yourself forever. And you can never get it back. And imagine what happens when you do that multiple times. You give a piece of yourself to five, 10, 15, 20 or more people. Then you meet the person that you want to spend forever with. And you no longer have that whole part of you. You've given pieces away, and you can no longer give those to the love of your life.
So, save those pieces for your future spouse.
If you have not had sex yet, wait. If you have, consider not giving more pieces of yourself away to people who are not your spouse. Sex was created to be between two spouses, nobody else. So we need to try to maintain its integrity.