The phrase "first glimmer" refers to the initial glimpse or indication of something. It is the very first sign or ray of hope, understanding, or realization about a particular situation or topic. Full definition
It did my heart good when this chair and ottoman arrived this week because we could finally see first glimmer of what this space will be like, even before we paint our walls. (theinspiredroom.net)
First the Glimmering Magnolia Dress and now the Lambent Amaryllis Blouse ($ 118). (effortlesslywithroxy.com)
At the first glimmer of consciousness, Kurzweil returns to the problem. (inc.com)