It doesn't work because of the syntax of VLOOKUP
=VLOOKUP(this value, in this list, and get me value in this column, [is-my-list-sorted?])
Since the 1st column of B2:B26 is B, it returns the value from column B so you just get the value itself.
So when you use the formula =VLOOKUP(2,B2:B26,1,FALSE) it just returns 2
If you switch B and A, you can get the value from A by getting the second column:
=VLOOKUP(2,CHOOSE({2;1},A2:A26,B2:B26),2,FALSE)