Compare the front-on pic of the young Obama wearing a blue shirt and the lower one of the more recent vintage from a similar angle. It does appear that the bridge is narrower now. That should not happen- noses keep growing all our lives. Is it possible he had some sort of nose operation after using too much blow?
All versions look like the same nose to me, and I’m a realist painter who does a bit of portraiture. What may make the young version look larger to you is that it is lit too brightly... the camera’s exposure setting, in other words. The brighter it is the bigger it will look because the light washes out the details that clue our eyes into depth, for example, whoch would make the feature seem wider.
It’s true that noses grow larger with age. They can also appear larger when people suffer from hay fever, etc... I’ve got pics of me enduring such attacks in my late teens where my schnozz is WAY bigger than today... it literally was!
But in the case of the brightly lit Obama youth pic I am certain the effect is merely lighting.