Re: Practicing Ki is dangerous?!
It sounds like either your teacher does not have the experience or knowledge to teach you about Ki in Aikido, or does not feel like you are ready to begin the study after only one month of practice.
If you can raise the question again maybe you can get a better idea of what your situation is. If he does not have the knowledge - by all means read both of Tohei's books on the subject, and ultimately try to fond someone capable of teaching you directly on the subject.
If he can share some knowledge, he may feel like he wants you to invest more time in Aikido before training in Ki. Different schools and organizations approach the subject (or ignore it entirely) at different rates or times in a student's training.
Ki was an interest of mine so I sought it out when looking to train in Aikido - but your choices may be more limited.