First of all every child will do things at their own pace. What it sounds like to me is that she is affraid that she is going to miss something.. For all of my kids I always had a couple potty chairs. one in the bathroom, but one or two somewhere else, as if someone is in there of if the door is shut they wont go in. If you can find where she likes to go hide at the pee her pants that is where you want to put her potty. Also I would stop using the pullups, you dont want her to think it is ok to go in her pants some of the time, and then not the rest.. you can get a cheat shower curtain at a dollar store and put that on her bed, then the sheets over it, that way if she wets the bed it doesnt hurt the mattress. My oldest son was just about 4 before he even started using the potty. Now my 2 year old , I had tried a time or two to get him to go and he refused, , but then all of a sudden started going on his own, and hasnt had a single accident since that day. It all depends on when she is ready. I let him pick out his underwear, I dont know if it was just that I stopped helping and let him do it himself, but she will get it, will just take time, I would just try putting her potty somewhere that she feels comfortable, even if it is in the middle of the livingroom, once she starts, she will catch on quickly. Maybe if it is really stressful, you can stop for a couple days, then try again.
Good Luck!