Like HBB, I was ready a few months prior to being able to, and so I was hoping that it would be on day X. However, both my instructor, CFI and many flying friends drummed into me that the chances would be that it wouldn't happen.
I think for the younger pilots who are aiming to soloing on their 16th bday, it's becoming more of the norm, but I don't think it should be.
I'm sure we've all had days where our flying isn't as good as other days, and so what happens if you have one of those days on "solo day"? 99% of instructors would simply say no, while a think a few would be pressured into letting you go.
I managed it on my birthday, but that's another story...
tKF