Am I the only one that assumes the wife was driving? OP was asleep on the passenger seat, was woken by their wife for the milestone and took the picture?
For the sake of symmetry, I would've liked to see her step it up by 10 or 15 MPH, get in another 85. It is a good, crisp photo though. Can't fault that.
It's a pointless phrase that is most often used on the internet.
It is used to whore for attention, because if someone is asking whether or not they are the only one, they should already know that the answer is "no," yet proceeds to ask anyway. Thus, "am I the only one" disguises a statement of opinion as a question.