Re: Practicing Ki is dangerous?!
My opinion only: esoteric subjects like ki can be approached all on their own (although finding a teacher isn't easy), but when approached through a physical practice like aikido, they need to be grounded on a foundation of physical practice. If the subject of ki interests you, then either pursue it as an esoteric practice independent of anything else, or if you choose to approach it through aikido, let the pursuit of ki go for now and focus on the physical training. Keep an open mind, do some reading or ask some questions once you've got a solid foundation in the physical practice (it will take more than just a few months), see what develops. If interest in ki is the only reason you are practicing aikido, I'd skip the aikido. If you have other reasons for practicing aikido, those reasons should be sufficient to fuel your practice for a good long while.