I’ll be Soseir your first few proofs and leave it at that. You admit b Yaakov, why should age matter?
There’s no proof from Yitzchok, he couldn’t leave Eretz Yisroel.
Moshe met Yisro’s daughters on his own first.
You really want to bring a proof from Dovid and Batsheva? Read the story again and tell me how he first saw her.
Nowhere in the Mishnah in Ta’anis does it mention a Shadchan. P’shat is that the girls said that themselves.
Just because you can prove that Shadchanim existed doesn’t mean that no one was ever allowed to date without them.