Hi Anna,
One quick question - more for self-reflection really...
Why did you use the settings that you did?
If you don't know (which is perfectly good answer!), then Manual is not for you yet. If you do know, then I'd maybe check your understanding. As David said above, I suspect you've got your f-numbers mixed up - f/22 is the smallest your aperture will go (or close to...), so it's really restricting the light coming in. ISO 1600 is also pretty high for outdoors, and 1/20 is slow for a portrait shot - both of which are due to the trickle of light coming through the tiny aperture.
I would
personally try to stick to either Av or Tv for now. It eliminates the guesswork, but still gives you control and helps increase your understanding.
The way I thought about it when I started out was as follows:
Tv - When the shutter speed is important
Av - When the depth of field is important*
I set the ISO at something constant, around ISO400 as your camera is pretty new.
As the ISO is now fixed, as you change either the shutter speed (Tv) or aperture (Av) you will also see the aperture/shutter-speed change to compensate. i.e. in Tv mode, as you speed up the shutter, the aperture will get bigger (smaller number) automatically. In Av mode, as you close the aperture down (smaller hole, bigger number, bigger depth of field) the shutter-speed will get slower.
Because your ISO is fixed, once the camera can't compensate anymore, either because it can't speed up/slow-down the shutter any further, or you're at maximum/minimum aperture, the camera will start to under/over-expose as indicated on the viewfinder or rear screen. You can then increase/decrease the ISO to compensate for this.
In reality, you end up changing ISO before this to avoid going to any extremes (you can't hand-hold a 5-second exposure, and f/22 will give pretty poor results).
Again, personally (and I'm sure many will disagree) I avoided Auto ISO at first as it became just another number changing in the viewfinder. When it's fixed, you get to know when and why to change it.
*Again, just to be controversial, I often flip these around. Normally an expert photographer with top-end great will know that for a portrait, DOF is the important thing so will set the aperture and adjust ISO to keep the shutter-speed high (at least 1/150) to ensure no motion-blur. BUT when I had a Canon 1000D with a kit lens, I would often use Tv to force a high shutter speed as I knew the maximum aperture was 3.5/5.6 (depending on zoom) which would be fine for a portrait and I really didn't want any blur. I would also increase the ISO to make sure it was correctly exposed. And this, is when you know you are ready for Manual mode.
(I say top-end kit, as the expensive cameras can produce stunning images at ISO3200 or more, so shutter-speed is rarely an issue. When I had my 1000D, ISO1600 was unusable!)
Sorry, that was meant to be a quick reply!