That's true, ruthla, but they are very conservative, and not super open about public nakedness. I've had some very private discussions with my Amish friend (woman, not man), and she wasn't comfortable discussing certain body parts by their proper names. I suspect that some things just aren't discussed frankly, iykwim.
Amish dresses are double layered, and can have nursing slits in them. Most Amish women that I know wean around the age of one by personal preference.
If your concernd about their comfort, ask if there's a place you can nurse the baby if there's men around. If you don't want to talk about it, nurse with a sling. They realize 'English' women do things differently, and aren't likely to say anything to you either way.