I nursed my son till he was 2.5 years old, gradually weaned so that the nursing was morning, naptime, evening, etc. so there wasn't a lot of "public" nursing when he was over 2. But I also called it nursing, and said "do you want to nurse?", so my son would ask "nurse?" when he wanted to nurse. See if you can change the word so it's a little less embarrassing :) - otherwise, people will just have to deal.
You're not an alien. Our culture doesn't know how to deal with this stuff, especially since the formula companies kinda convinced a few generations post World War 1 (after powdered milk was created) that formula was better than breastfeeding. Several generations have NOT breastfed, so it's not taken for granted like it should be.
My attitude was that it was my baby's health, my choice, not infringing on someone else as I was not flashing my hooters around when he nursed. I tried to be as private as possible to respect others, but I wouldn't sacrifice cleanliness, etc. for someone elses' sensibilities.
You go, girl!