TransGo has a kit that they call the 700-2&3 which means it is a manual / automatic kit. The kit has the option of full manual shifts.
Full manual shifts means exactly that, you must up shift and down shift the tranny for each gear.
If you put the shifter in 3rd at a stop, the tranny is in 3rd gear.
You still use a standard converter as you mention, there is no clutch like a manual tranny has.
Dont worry how old you are... it is the mileage on your body that adds up.