Don't let that be an obstacle. Lots of us gals are over 6 feet tall. I'm 6'2" myself.
You don't have to disclose your build, but the way to go about that is to find the kind of outfit(s) that best suit your body type. There are women of all types of physique out there. Try to spot the ones whose body type resembles yours most closely and try to replicate their outfits.
Pick a safe setting and plan the logistics of the outing in advance. Consider contingency plans in case something goes wrong - One time, the heel of my shoe came unglued just as I stepped out of the car. Fortunately, I had a backup pair, that sort of thing.
If you have friends you can trust with a secret (or just don't care if people know), you might want to invite one or two along. When I was finally ready to buy a wig, a GG friend of mine volunteered to come along to help. In the end, she was the one who found my first wig. It was a lot of fun.