As I have said before, I started Aikido as a means of getting exercise AND learning something useful at the same time.
What I have found is what can only be described as an extended family, both through my dojo, and places such as this and aikido-l!!
The art has got into my head, and my heart and even though it is at times hard or frustrating or tiring it never becomes dull. Even my first 'bad' night where nothing went right and I felt like I was operating at about 40% in speed, stamina and strength, the people around me lifted me in a way I have never felt part of in anything I have done before.
Aikido is rapidly becoming a very large part of my life and all I can think is why did I leave it so long to give it a try!! (I will be 30 in December!)
As to carrying on, it is in me now and a future without it just doesn't seem right.
I get the feeling a lot of people will struggle to put into words the why and wherefore of their continuing Aikido because there is something to it that words cannot describe.
It is a very human thing to question yourself in this way, but perhaps there is no hard and fast answer to all your questions.