A couple years ago I renewed my passport. When the new passport came in and I compared the picture page of both, I went through a similar feeling (basically comparing my 20YO to my 30YO) noticing the bags under my eyes getting darker and just general expression looking more docile. After having my first born, my hair began to gray fairly rapidly (thankfully no balding yet) and when I look in the mirror, sometimes, it just feels odd.