Sure, I understand. It doesn't seem to be a great source, but it's a source nonetheless. And I definitely remember that Capcom confirmed that Nero was NOT a son of Sparda.
We can also hold truth around Dante's age from it, as I already researched the time-line earlier. The source claims that Dante is around 28/29, and that it takes place not long after Devil May Cry 1. We know this to be true, because Dante was 28 in Devil May Cry 1. As Trish states that Dante lost a mother and a brother to evil 20 years ago. Dante's mother died when he was eight years old. If twenty years had passed, he'd be 28 in Devil May Cry 1. And he'd be 29 in Devil May Cry 4, because Devil May Cry: The Anime takes place just before that. So we know Dante's/Vergil's age throughout the time-line. After Devil May Cry 4 it's anyone's guess. As I said earlier, I just put him in his 30's to 40's for Devil May Cry 2.
Also I always think on Devil May Cry 4 as sort of Devil May Cry 3, but for Nero. And in Devil May Cry 3 for Dante, he was 18/19. Nero held a lot of maturity. He was also a fine warrior. I think he was at the age of 18/19 in Devil May Cry 4, just based from those three things. That would make Dante around ten years older than him.
If Vergil was alive still (Or if he is) then he'd be Dante's age in Devil May Cry 4, which is 29. If Vergil had sex, let's say, even at the age of 16, then that would mean that Nero is 13 years old in Devil May Cry 4. He does not look 13 years old to me. The youngest I'd say he looked is 17. But I think he's around 18/19 as I stated before. So he's either 10 years younger or around 11 years younger than Dante. So Vergil would of been 10/11 when he had sex with the supposed prostitute. And as I stated earlier, the Devil May Cry 4 Novels weren't confirmed as canon. And if they were, it goes on the basis that not only did Vergil have sex with a prostitute, but he did it so young.