The Internet has become popular enough that governments care about what happens on it. And it's not just European countries, US states too (at least for age verification).

More specifically for your two points:

Encryption

It used to be that very little Internet traffic was encrypted, much less end-to-end encrypted. After 2013 (Snowden revelations), this changed, e.g. messengers started to E2EE, many more websites than previously started to use HTTPS. So all we are seeing now is the reaction to those positive changes...

Age verification

This has to do with mobile devices more than anything else. I think a lot of parents now just hand their children smartphones or tablets and may then be surprised that their children can then access things they don't want their children to access. This was less of a thing in the desktop era because it was easier to see what children were doing online if it was happening on a huge computer in the living room...

Now personally I don't think anyone (including young people) should ever be prohibited from watching or reading anything they actively want to see. For preventing young people from accidentally accessing porn, an "are you over 18" banner ought to be enough... I don't think people who want to prevent that kind of access want anything legitimate. But you asked about why it's happening now and not at another time and I think this is the answer.

Sidenote: I remember reading that when television was newly introduced in East Germany, it was still able to be somewhat critical of the regime; after some years, this stopped because a lot more citizens were able to watch it. The equivalent of that is currently happening to the Internet.