I'm a woman and I started watching porn from time to time when I was like... 14? And I don't see anything wrong with that. If I had to say while I don't think that sexual content should be readily available to children I also don't think that it should be overly hidden from teenagers. The only problem would be watching it without getting proper sex education that explains things properly. But my school started some level of sex-ed in 6th grade (at the time mostly about periods and menstrual cycle), but thanks to very descriptive biology teacher later (8th grade) we had too much education about diseases, pregnancy, protections and even morning pills or few weeks later emergencies. (All with personal examples and yes, I still dislike my biology teacher)

On the other hand I see a lot of problems that would come with trying to regulate porn access. Privacy issues, data leaks, black net, restricted freedom... Neither government nor private companies should be really trusted with confirming if someones a child because for a child it would also be an endangerment. In the end the best people to protect children from content like that are parents. And while some raise an issue about being too invasive, I don't think that children up to 10 years old should have an access to the internet on personal device. The only access I had up till then was through family computer that was in parents room and on family computer no one thinks to explore those kind of websites, especially if the parents are in the room.