Do I think my abilities will keep getting better as I get older?
Duh! Or why keep doing it? Aikido is the art of neutralizing aggression -- why assume that a younger, more aggressive practitioner is naturally "better" than one who is old, less (obviously) aggressive, and wise?
My first sensei, Norio "Mike" Mamura (may he rest in peace) was and on the mat teaching until shortly (days) before he passed away at the age of 82. I'd only known him for 20 years, and he was kicking butts the whole time I knew him -- a sincere attack meant a serious fall/pin/lock was coming your way. He embodied the art of Aikido: technique executed not with strength, but with ki -- a proper application of minimal force in the right time and place to ensure maximal results.
He was the was a "typical" frail old man, 5ft-3 and maybe 120 lbs dripping wet, with a history of ailments as long as your arm (battled cancers, wore a pacemaker, walked witha cane), but none of that kept him from practicing his beloved art, and none of that kept him from constantly working at improving his aikido. And he really did get better as he got older
I can only strive to follow his example.