Re: In a quandary
Mario, there is no martial art or any other kind of magic bullet that will protect you from all harm. There are bad and dangerous people out there certainly and you could be called upon to protect yourself or others from harm. Whatever art you study will help, but none is one size fits all, regardless of what various proponents may claim.
Awareness, both cultural and situational, will help you identify hazardous situations so you can avoid them. Regardless of your martial art, you will learn a few techniques that will generally work in most situations and give you the opportunity to escape or summon help. There simply isn't anything out there to prepare you to defend yourself against 27 ninjas armed with machine guns - it doesn't exist.
If you are studying aikido specifically for self-defense, I would recommend that you take a self-defense course instead. Aikido can clearly help you defend yourself, but most instructors are unaware of the legal ramifications of self-defense actions in their jurisdictions and are equally unaware of the prevention skills that can help avoid a physical encounter. If they are, they rarely teach those skills. Honestly if you have to use your aikido (judo/kenjutsu/karate/boxing/BJJ/krav maga/you name it) you've probably already made a number of mistakes.
If you aren't concerned about defending yourself as your original post suggests, then stick with aikido - it's fun, it promotes good health, you will be training with some great people, and you will actually learn something that will help you protect yourself in some circumstances.