The speed will change automatically in Aperture mode, the more you go up the scale EG: one stop up f5.6 the shutter speed will drop one stop. you could have taken this at about 125th sec at f16, still fast enough for hand holding or if shaky like me on a tripod, did you manually focus or auto focus? it looks like auto focus with the focus point not in centre of frame (the focus point can be moved, have a look at your manual to make sure you have not moved it from centre position), when you focus manually do not just use the centre to focus! The whole screen can be used, hope this is not over your head at the moment, just remember that if you just want a subject in focus and the rest of the background out of focus, then use a shallow depth of field like you have done at f4! Then the more you go up the scale f5.6, f8, f11, f16 and so on, the more you go up the more the depth of field gets so at say f22 most of the shot would be in focus, to practice this put camera on tripod and then do not move it, place some objects on a table diagonally going away from you, then at f4 focus on the object nearest you, then take a photo, the objects behind will be out of focus, now change to f5.6 and take a photo, keep doing this right up the scale until f22, now every thing will be in focus, this is how depth of field works.