Aikido is a mixed bag, and depending on what you expect you can either be disappointed, or excited, or go through waves of both.
It was frustrating for me the first 6 months, mainly due to learning in a different language than my native toungue. I actually stopped for 5 month, then got back into it and things were different.
At some point, things clicked, the how things worked, when they could be practical or not practical was making more sense.
Based on some scuffles I had in the past, I saw how I could have ended the fight more peacefully with certain techniques.
Not only that, I realized that with my attitude I could have just prevented the fight by not allowing myself to get involved in the other persons tornado.
Of course life will give you challenges until you master these concepts.
As for exercise and the idea about beating a sport fighter, the fact is that those guys train with getting their body beaten, like ol' rocky with the stomach punches. [stings after awhile...] So in a sense that is a separate, yet connected, discipline altogether.
Im trying to mix the two, the yin and yang. Ill have to admit the harder stuff at my age isnt how it was when I first dabbled in kick boxing in my earlier years... back then punches didnt phase me, but then again I wasnt fighting someone larger than me.
So, in the end, its all good. You have some experiences in some pretty cool arts, boxing being great for footwork... etc.
Whatever you do, have a good time, and enjoy - and keep us posted with your Aikido.
You say your 30... your still a young whipper snapper.