1. PISA showed it? Vietnam never participated in PISA. Maybe you are talking about Viet elites in Germany who managed to grab their children and flee the jungle? They don't represent the general Viet population. If German media praises you, it's because Viets are a docile and obedient people. They want to contrast you with their recalcitrant Turk immigrants, who commit crimes everyday. And you took their flattery seriously
.
2. Even forgetting the insuperable hurdle of your IQ, you cannot acquire nuclear weapons because you are a signatory of the NPT. If you try to, the international community will finally realize that you are a rogue state and sanction you like they do to North Korea and Iran. And China will bomb your reactors (like Israel did to Iraq), while the rest of Indochina cheer us on. They know you cannot be trusted with nukes.
3. Before you were a tributary state, you were under 1000 years domination, when China had direct rule over you. You are right when you say on sporadic occasions, you resisted successfully (Viets love talking about "Trung" sisters). But the 1000 years was a continuous, almost uninterrupted era. Thus, it's silly for you to cherry-pick the rare instances of resistance.