It is OK. If you are tall, you are tall, adding a few extra inches does not actually make you perceived as taller. Tall is tall is tall whether you are 6' or 7'.
Wearing heels gives you a few advantages though:-
1. You have a jolly good excuse to be tall!
2. Your walk will be elegant so you will carry the height better.
3. You will feel more confident wearing what you like (your heels!)
Try it and see how it goes. You will be surprised at the reaction.