Bird's defense

If black takes the knight you don't really have to mess up your pawn structure, since you can take the black knight off f3 with your queen.
Maybe 4. Ba4, Nxf3 5. Qxf3 assuming he wants to take the knight?
Or 4. Nxd2, exd4 if you want to initiate the trade and then continue to fian-chetto your queenside bishop with b3 and Bb2?

don't worry it
just move ur b to c4 and let him exchange
later do fian chat and develope ur night to f3 by moving to c3, e2 and you get there
it is quite tigh and fine . in end game you are intiate the game
It is reasonably sound so dont expect a refutation. As best I recollect, white should exchange knights, when bishop is attacked by c6 go to a4, then play c3 [possibly d3 first] and try to force dxc, bxc giving you more center pawns. Then you gradually roll them forward: f4, d4 .... Black is very active so you need to be patient and careful and you'll have white's normal , long term small plus in the Ruy.