Thank you. I am probably an inch taller than you and also thin, but not "skinny" by any means.
I almost never go into a physical store anymore. There is an Ann Taylor Loft near my house, where I buy lots of stuff, because they have my size, but right now I am not so happy with their stuff. The Talbots next door constantly tries to get me to buy stuff there, when I go in to buy stockings or other little accessories. Besides the fact that the clothes look like they are for old ladies (even though I am an old lady, I don't dress like one), the size 2s there swim on me. I buy a lot of stuff from Banana Republic and Gap; there is a Banana Republic petite store in a mall about 18 miles from here, so maybe twice a year I go there; the rest is done on-line. I didn't know the Gap had petites on-line, as they are not in the stores. I have found tons of skinny jeans that fit me! However, their sweaters and tops are a little big on me; they don't have xx small petites (even though I am not xxsmall).
Bathing suits, well, I only buy them from Athleta now. I found one tank style, halter top that is flattering to me, or at least as flattering as a bathing suit can be.