Re: learning 2 arts at the same time
I do know people who cross-train, but for many, the lines get blurred. Some can handle it, and others can't. Since a proper foundation is crucial in beginning any martial art, I recommend that you stick to Aikido for a year or two, and then venture out elsewhere if you feel comfortable. By that time, you'll have enough Aikido under your belt to know if your other training is having a negative effect on your Aikido. If you do cross-train, let both instructors know, so that they can watch for and recognize any negative influence in your technique. Also, choose your "second" art carefully, as there are many which are akin enough to Aikido to make it an easier undertaking than it might be with other more contrasting arts.