Well, not exactly. In the EU, as you should be aware, the legislative ability of national parliaments is limited by the various EU treaties, which make EU law superior to national legislation in many respects.
Indeed, but should any individual nation decide to change it's mind and ignore the EU, then the EU would have to try to enforce it somehow. EU law is only superior to national law while national governments voluntarily accept the superiority of the EU law.
Either way this is a side issue to the legality of the age laws.