I find it an interesting topic. I do believe social media needs some form of regulation but at the same time I think it goes hand to hand with parents responsibilities.
Problem with social media is how toxic it can get. For example, when someone does 1 wrong post.
For a teenager it can be devastating getting death threats on a daily basis.
Is the solution requiring an id to be 18+? I don't think so. I believe social medias just need better security in general to prevent things like death threats or things like scrapper sites within facebook and stuff.
Do I believe you need parental consent to surf the web not just social media? Yes. Each parent is responsible for what their kids are watching. As a responsible parent you should make sure they aren't watching anything violent, discriminatory, or illegal.
Do I think a law is needed? Personally, I think it should be common sense but I do know how some parents just don't care much about what their kids do.