Vintage 1969 Flower Power Dress

this was my mother's dress from 1969 time frame. the seam has come undone a little in the armpit (see photo) which is an easy fix for any sewer. its from a smoke free home though cat friendly. I wore it when I was a size 12 34C but it says a 15 on the tag. I'm not certain the size but it would not fit me now and I'm a size 14-16 38D. Flower Power!! Because it truly is a vintage dress, the price my mom paid in 1969 is not appropriate to compare to now. after discussing with a local vintage store owner she said she would price it in the low $70s.