The difference is that women were never going to be accepted as the equals of men without activism and changes in social norms. (Male) teenagers simply needed to wait a few years.
Waiting a few years helps when the problem is getting laid and make your own choices how to spend your money. It does not fix
- school education (at the age of twenty, you either have or haven't had a decent school education, second chances are the big exception)
- access to college (dito)
- unwanted pregnancies (especially when there's no legal abortion)
- the side effects of being beaten up whenever your parents considered it appropriate - or even sexual abuse.
- and last but not least a very important point that I missed in my last post: conscription
For Boomer teens, access to college education was already increasing significantly during this period.
So did woman's rights, but that doesn't mean the women's rights movement became obsolete.
As for the last two items, I'm not sure how much of a problem they were at this time, but sex between teenagers seems hard to regulate, especially since grownups have always expected it, so they're unlikely to be to hard on teenagers doing it with each other.
IMO a strict but unenforced law combines the disadvantages of strict and lenient. That is why sexual abuse was hardly ever reported theese days. The laws exist for a reason and must be designed to serve a purpose.