>>3315994Age is not the problem, the way you act and look is probably what you should focus on.
Some general rules:
1) Be polite, don't push anything, keep it proffesional. It generally helps if you're speaking clear and have overall confidence. Explaining with shaking voice, not knowing what to do with your hands and general uneasiness talking about your own work doesn't make a good impression. The way you look and act influences people and their decisions a lot. Bringing a portfolio helps a lot.
2) Before you even start, it's good practice to ensure the person you're speaking to that you don't want to force them into anything and they're free to decline at any time without any reason. Especially for nude shoots. Describe the project, it's goal / artistic value. Make sure they understand that it is nude photoshoot. This can vary, based on how well you know the person, but usually asking people to shoot them nude when other people are present is frowned upon. So do it in private... either when speaking with the person without anyone listening, or just inviting them for a coffee at some public space / your atelier to talk to them about your photography project. It's also usually easier to convince person to this kind of shoot if you've built some trust between each other. For example, you'll have way easier time convincing a model that has already attended 2-3 shoots with clothes on or budoir etc. than a random girl on the street waiting for her bus.
3) explain why the person you're reaching out to would fit and make an offer (either offer money or TFP, you can already guess which will get accepted more often). Usually helps if your reasoning is something more than "they would look good naked, I'm sure".
4) if the person declines at any point, don't push it. Based on the way they decline, you can try asking them, if they by any chance know a person that might be interested.
Any specific reason you require them to be 18 year old? Shit's sketchy