I have learned a lot of great stuff from people who were lower graded than me. You can learn from anyone, regardless of their rank, I think. Teaching/learning technique is important and I understand where your doubts are coming from, but personally I find it very very important that apart from technical knowledge a teacher is enthusiastic about aikido and is able to create a positive atmosphere in a dojo. So it sounds like you might be in a good place, at least for now. Enjoy!