I hope that it is with someone you know and trust and not a random hookup - not because of the sentimental value but because they will want to put your needs and comfort before their need to cum. I’m not saying a random hook up won’t do that for you but there’s security with someone you know.
Surely you know you need to make sure your insides are clean. Google is a friend. I suggest not eating much day before or the hours leading up to it. However, it’s different for everybody as our bodies are different - totally depends. There’s douching but I haven’t douched before. Shower before you have sex to make sure you’re clean inside and out.
It’s your first time, it’s going to hurt no matter the position. It hurts less for me when they enter and we’re both on our sides. But I can’t really say for you what position would hurt less for your first time but if other followers would like to suggest positions then please reblog or message me suggesting positions and I’ll post it. And then you can choose.
Please understand that you are in control. Forget porn, if you feel you must be submissive and not speak up when it hurts too much or they’re going too rough or too fast then you’re not ready to have sex. Staying silent is the ONLY thing you SHOULDN’T do.
Also accept it’s going to possibly be awkward or whatever, it’ll take the nerves away. You don’t need to perform or doing anything that’s not you. Porn stars are actors, you are not. That being said, if it starts to feel good, let that sensation take over you, allow it to move throughout your body. If you moan or grunt, then let it out, there’s no shame.