Olive oil is extremely bitter - has it gone rancid?
Good EEVO from young olive trees will have a green tinged yellow colour, be astringent or peppery tasting (astringent is different from bitter, as in lemons are bitter, spearmint is astringent)

The astringent taste is a mater of preference. In my experience most people don't like it

Olive oil that has gone rancid is yellow, smells more like peanut oil or just like old grease, and tastes bitter

Oil from Dec 2012 would most likely be rancid by now, unless it was stored in light and air proof containers