Question

why current flow in opposite flow of electrons?

Answer 1

Because the alternative would be worse.

If you defined electric current to have the same direction as electron flow then what would you do if the current was being conducted by particles other than electrons? Say, protons? Would you define the current to always have the same direction as the flow of charge carriers? In that case, the direction attached to the current would carry information that's not very useful most of the time (the direction in which charged particles are flowing) rather than the far more useful information of the direction in which charge is flowing overall. For example, the direction of the magnetic field is determined by the direction in which charge flows through the wire, not the direction in which charge carriers flow through the wire.