Near 50 and the exact opposite. Mentally I'm sharper than ever (low bar) but physically starting to feel old. I still have some fairly aggressive physical ambit

Near 50 and the exact opposite. Mentally I'm sharper than ever (low bar) but physically starting to feel old. I still have some fairly aggressive physical ambitions but wondering if I've got what it takes to accomplish them. 30's through mid 40's was the best physical segment of my life.