So, no, there is no official line at 18-21. Especially in the EU.
That is hilariously general. You're conflating a lot of different nations there. In practice; its different depending on the nation, consent is usually 16 and alcohol is ~18.
40% of the EU has age of consent 14 or lower. (Germany, Italy, Portugal, etc.) 78% of the EU has it at 15 or lower (France, Sweden, Denmark, etc.)
No 'official line' at 18-21.