Welcome to AikiWeb! I think it's great that you're so active at 61. I'm 42 and after 11 years of aikido, I'm sore in the mornings too.
I think some aikido dojo would suit you while others would not. Go visit several that are a reasonable commute. Talk to the instructors and check out their attitude.
Also, I would talk to a doctor and get them to clear you before starting. You don't want to reinjure your leg or tear something by starting vigorous exercise after forced inactivity.