Can I try porn once without making it my whole life?
Yes.
One project can genuinely be one project. You can try it, get paid, decide it was interesting or awful, and never do another.
People sometimes talk about porn as though doing one scene automatically gives you a permanent new identity. Real life is less theatrical than that. People try things. Sometimes they discover they love them. Sometimes they discover they absolutely do not.
The part that can outlast the experiment is the material. You can stop working tomorrow while a film you agreed to publish continues existing. That is why the career decision and the publication decision should be thought about separately.
If you are comfortable with the publication terms, a one-off production can actually be a cleaner experiment than opening a creator account. An OnlyFans account immediately gives you an ongoing business: content, promotion, subscribers, messages, pricing, planning and the permanent question of what to make next.
Maybe you want that. Maybe you only want to know what doing a real explicit shoot feels like.
A production lets you test the work itself. You agree the concept, fee and limits, turn up, do the job and let the production handle the technical side afterwards. Then you have real information about yourself instead of theories.
Did you hate the camera? Did the sexual part feel surprisingly normal? Did you love acting? Did you like the set but still want to keep your face out of future work? Those answers are much easier to understand after one controlled experience.
Afterwards, maybe there is another film. Maybe photography. Maybe a stage name and a bigger plan. Maybe nothing at all.
Curiosity is not a five-year contract with your future self.
One thing I would decide before the experiment is what you want to remain private if you do stop afterwards. Face? Stage name? Voice? Tattoos? The less public identity you build around the one project, the easier it may be to let the experiment stay separate from the rest of your life. That does not erase the material, but it can reduce how much of your everyday identity gets attached to it.
And if you end up loving the work, you have not lost anything by starting small. The second decision can be much bigger than the first because now it is based on experience rather than fantasy.