Jeez, you people do have a firm grasp of the obvious. After all, who would have thought that natural ability, toughness, determination, etc. would be important attributes for a fighter?
The problem is no one was speaking of becoming a professional fighter or even vying for the title of Bad Bully on the Block. It was simply a question of the efficacy of Aikido as a means of self-defense, which doesn't seem to much to ask from an activity that calls itself a "martial" art. Then again, maybe you pay your monthly dues and attend classes to work on your clever quips.
No we foolishly respond to a loaded question. Somehow I am sure you already know the answer.
Find a dojo that trains for self defense. That could easily be an aikido dojo or something else. People gave you good advice for what to look for - and yes its pretty obvious. Why again are you asking?
I mean if its so obvious.