That is so true! how many men even think about names at all until their wife/partner is pregnant. Honestly maybe they like the idea of partially naming their children because theyr’e their children and they represent them in a way but it’s more then that for us.
Psh, I’ve been picking out my kids’ names since I was 14 years old! I remember my first favorite name for a girl was [name_u]Aspen[/name_u] [name_f]Sophia[/name_f] because when I was in 7th grade because I met a little girl named [name_u]Aspen[/name_u], and I got [name_f]Sophia[/name_f] from [name_u]Golden[/name_u] Girls, my favorite show. I didn’t start thinking about boy names until I was in 9th grade, which was kind of when my name love started. My favorites then were [name_f]Kaydence[/name_f] and [name_m]Karter[/name_m]… 
Now, I’m in a committed relationship with a name prude, which is really hard because I love so many! And he barely likes any at all.
Lol, but basically to answer your question, I think it’s common for girls to pick out names at a young age. When ever I mention names to other girls my age, I see their eyes light up a little bit like they have almost been dying for someone to ask.
I have names that I love and would definitely use on a future child, and I even already discuss them with my bf, but I know that I would have to wait until I meet my child to know for sure what name would best suit him or her. I’m 23, btw.