i have a lvl 48 ne druid and a lvl 12 taren druid which one shuld i stay with

stay with ne its perfect for you ;)

Stay with the NE, higher lvl won't waste so much more time lvling then.

But it totally depends on whether you like playing horde or ally, coz that is basically the question you've asked and that is toatlly up too the player's personal choice.

go for the faction that you have your friends on, its no fun if your friends are on another faction