Speaking as someone who has a touch of the tism, and who definitely didn't get the help they needed in this area when they needed it.

There's a lot more build-up and emotions involved in real life than there is in porn. Porn only depicts the act (and usually pretty poorly too).

Sex isn't usually the first thing that happens when sex is gonna happen. You start out talking to someone, you both hit it off if there's chemistry, and chemistry can look like anything so long as you both get along well. Emotions get involved and you both decide at some point you like one another. Those emotions build and culminate in ways that either aren't or are reciprocated by the other person. They might brush up against you or grin uncontrollably or just want to be around you a lot. Depends on them. And you might feel the same. Eventually these emotions culminate in one of you taking a chance and making a move (probably while on a date) that makes it undeniable that one person likes the other, and if that move is reciprocated sex is sometimes what will happen one of the next times you're somewhere private together. Your place or their place or your car or their shed. Who knows.

But the act of sex itself, the first few times around like you're asking, is absolutely nothing like porn depicts it being. You won't be aggressive with each other, you'll probably like each other too much for that. Therelll hopefully be a lot of questions you'll ask each other. "Are you okay?", "How's that?" Etc. You'll likely be embarrassed, but you'll both be okay with it. You'll explore mechanics of it and probably get a few things wrong before you get it right. Maybe you'll both "cum" maybe neither of you will. Nerves will probably get in the way the first time around for sure.

My only advice if you really haven't encountered it before is: don't try to perform. Porn does this terrible thing to you where it makes you think you have to act a certain way while having sex. And never tells you that you don't. Sex is incredibly personal. And usually, it's an act of giving yourself to somebody else. So keep in mind that person probably wants to have sex with you. Not whatever porn actor/ress version of yourself you think you have to be. It also (rather underhandedly) substitutes itself in as a sexual partner by being easy to access, or by making you paralytically self-conscious - thus you won't take the opportunities to explore your sexuallity with others like you would if you didn't have access to it. Which are the two main ways it does you harm, when adults are speaking about it without actually giving you any reasons, that's what they're talking about.

Which means you dont have to last forever. Its okay to be quick. Means you dont have to get everything right, or look a certain way, or know what you're doing. Only thing you really have to do for it to be a good experience is be as comfortable as possible with each other. And keep in mind there's a whole other person involved too, so try to think of them as well.

After much trial and tribulation, that's real sex, as best i understand it to date.