He wasn't too keen on the idea when she first told him about it.
Golf he did not take up till comparatively late in life; and, though he became keen on the game, he never attained more than a moderate proficiency.
I'm not too keen on that part.
As a warrior who spent his adult life at battle, he wasn't really keen on how to comfort a woman who had seen three things she'd likely never witnessed before in the span of five minutes.
I am quite keen on the idea of mixing cedar wood cladding with areas of render.