My 25th birthday is in just over a week. I don't feel like I'm about to be 25. I feel like I'm simultaneously 19 and 30. I lost most of my late teens and early 20s to mental illness. So I feel 19 because mentally, I get along better with people that age. But my body (and also other parts of my brain) feels 30. Because I've dealt with so much shit, I feel aged. 

Basically I feel every age except the one I am.