Right there with you, sister! I was SO anxious the first time I went to get fitted for shoes. I thought they would be so rude, or otherwise incredulous that I was buying running shoes. I was totally psyching myself out.
The actual experience was pretty painless. I felt no judgment, in fact, no mention at all was made of my size (I think I was about 160-165 then?). The shoes were expensive, but worth every penny.
It's so tempting to let fear hold you back, but we have to show fear who's boss!
Go get some shoes!