Though there is no special dress code both for men and women and you can wear whatever you want, both sporty and classic, in any case you should keep not that mini :) In case you don't want be flirted by Armenian men. However not wearing short clothes will not prevent you from not being filtrated. Whenever you're attractive you'll feel the looks around you :) But do not worry they will do nothing to you. It'll mostly finish with compliments about your beauty. Let them admire you and your beauty and just walk ahead.
In case you want a conversation.. Just answer to their compliment and leave the continuation of the new starting story:) They will invite you for cafe or dinner or even will start dating you :)
Try not to feel discomfort from the looks around you. It's just because you're different from Armenians with the appearance:))
Despite all these you should not forget that Armenians are one of the most hospitable people in the world and they're always happy to host you in Armenia.