User blog comment:Vaffisuco/Segments Blue by Sele-P Tentative Translation/@comment-1523675-20180524073051/@comment-1523675-20180531041848

My intuition says 初めてのキス refers to the first kiss with the girl's boyfriend, not the very first kiss in her lifetime. But I can't decide unless asking the author.

You can upload this translation on this wiki. I'll make some more slight edits.