To be comfortable, I think you need to choose the environment carefully for your first shopping excursion. Pick a store that is part of a national chain (and may have corporate policies in your favor) but go when they are not terribly busy, say on a weekday morning. In my neck of the woods I would recommend Dress Barn. Find something -- anything -- you like, make eye contact with an SA and ask, politely but confidently, if you can try on the item. Once you make it to the fitting room, you're over the summit and it's all downhill from there. The second time will be easier and the third time will feel completely normal and natural.
- Diane