My apologies if someone already pointed this out and its cannon, but I was literally in the shower thinking about the idea of "the wall". It is threatening because it implies you could be drop dead gorge right now but you could wake up tomorrow and bam you have been transformed into an ugly old bitch! No one ever explicitly says that, but that is what is implied by "hitting a wall"; a sudden, catastrophic stop where you are mangled at the end. The underlying message is even "pretty girls" better settle or else wake up one day as unlovable hags. But of course that is not how aging works. It is part of the slow dance of change and time. Nothing to be afraid of, nothing that will sneak up on you unless you are dragging an idea of your past self behind you. So no rush, ladies. Also, less philosophical, but anecdotally I'm 39 and way hotter now than I was 10 or 20 years ago. Had way more creepy gross old male attention when I was an awkward 19 yo though! Maybe that is the wall they are talking about; the age at which 72 year old perverts think you no longer look like you are in high school.