Not only will they find it, they’ll end up going to the sketchier sites that don’t do the age verification because they’re not well known enough and not following the laws and they’ll likely get something infected on the computer/network or worse.
It’s like that time we declared a war on drugs and then there were no drugs. Wait, actually that led to a massive black market and tons of violence.
Point being, you’re not gonna stop it. You’re just gonna make it less safe.