There are two issues here.
Firstly - your own perception of being a tall women and how other women feel about that. For some reason (and I'm guessing that one woman, some woman, sometime in your past said that she was intimidated by tall women), you feel that your height intimidates. You have taken this comment to heart and believe it to be true for everyone.
Secondly - Height does give you an element of Yang (strength, power and authority). So in a way point one could be true. But I would like you to consider yourself as a whole, rather than just your height. There are many elements of your physical appearance and personality that may actually balance your height out and make you approachable.
Go through the checklist of Yin and Yang physical traits here and see if you are overall more Yin or Yang (or balanced) with your physical presence.
Now consider your personality. Read the table below and mark which most applies to you (the majority of the time, not what you "can be" if you "have to be"). You may sit one side or other of the mid-line - or you may sit right in the middle between the two personality traits.
Once you have completed the table above, count up how many ticks you have put on the Yin side and how many on the Yang side. Anything that falls on the mid-line can be ignored. Then notice if your personality is more naturally yin or yang?
Now your combine these results with those of your physical appearance and you can start to see if you really are intimidating or not. Whether your physical traits and personality really are more one way than the other.
If you are naturally more yang, then consider adding some extra softness or yin elements to your outfits to balance your personality and make you appearance more approachable.
You may discover that in fact you are fairly balanced naturally, so that your heels and height are completely fine! Or in fact maybe your personality is naturally more yin and you need those heels to give you some strength!
If you are interested in a really comprehensive set of questions and tests to discover more about your overall yin and yang, your entire physicality and personality (the above is a shortened version), this is available in my 7 Steps to Style program.