Sometimes just jumping in the deep end is the fastest route to confidence. Of course, you want to do it in a safe environment with people you trust but it is a great way to feel comfortable in more feminine clothing - you'll probably find you don't even notice after ten minutes or so. I'm a bit different from you, I didn't feel I could pass unless I was in a dress or skirt... I only wore pants once in my preliminary/pre FTE phase and felt self-conscious the entire time. I'd suggest that if you're passing in pants then a dress will be no problem. Mind you, maybe dresses and girly stuff just isn't your thing - it isn't for a lot of cis women. Just were what your comfortable with.