I can relate. The thing about social anxiety is that no matter how hard the person tries to overcome it, it may take a lot of time. I have been trying to overcome my own social anxiety. I am only 16, but I have taken college classes already! I am very independent, smart, and creative, but I could never go into a store and ask a clerk something. I don't know why. It is something I can't seem to control or get over. I am working with my counselor now, but I still can't seem to get over it. Your daughter may be able to go to school and travel, but maybe talking directly to strangers and others causes her anxiety.
Social anxiety could be broken down into other types as well. Some people don't like public places, groups, talking to store clerks, anything like that. For me, it's groups, small places with a lot people, talking in front of groups, etc.
I try to deal with it an ddo my best, I encourage myself, but no matter how hard I have tried it has not worked. Sometimes I try and I start to talk to someone and I can feel it coming on. I force myself, but I can feel my face getting so hot. My heart starts racing and I can just tell that whoever I am talking to knows something is up.(or at least it feels that way)
It is very hard to deal with. Just encourage your daughter. I wouldn't want my mom to force me into talking to a clerk, but it could be a good thing. I am starting to practice my talking with others through therapy. Maybe your daughter can do the same. Don't force her to go up to a store clerk and ask for something just yet. Start slow and practice. She doesn't have to do it all at once. Just be there for her and encourage her.
I have come a little ways since starting therapy, but I know it takes patience and I have to keep going until I get over it. It takes time. And, I think it is great that you are there for her. Be understanding. Be patient.
I know I am speaking as a teen to a mom. From my point of view, this would be the best thing my mom could do for me. I guess this is my advice to you.
Just continue to be there for your daughter. I hope everything works out for your daughter. And I hope this helps you. Take care!