Gracais GacjanaK,
First - it's looking pretty amazing for your first rendering.
(I think you have some experience, am I wrong?)
Things to consider:
I am noticing you set the sun to power of 5000. This is not suggested. If the sun is stronger than 5 something is wrong.
It appears that your sun angle is on the opposite side of the house - so that the sun is not coming into the window. Any light that is too strong will slow the render engine down as it will need to constantly perform error correction and ray rejection.
Have you set the glass in the window to be Architectural>Common ? (if not, this is what you want.)
If you want more light coming in through the window, build a sky portal like
this video tutorial explains.
Actually, direct sunlight through the window is not recommended by some artists I've seen, as it can be distracting with the strong shadows. Also getting the right exposure for your camera with direct sunlight can be "challenging".
The floor material looks like it was freshly sanded and has no finish. Have you seen our
kitchen with Twilight Render video tutorial? It talks about the floor material and the LED cabinet lighting.
Is it your intention to have the ceiling can lights off? What about the two spots over the sink? They may be "on" but maybe you need to add a point light inside to light up the interior of those light fixtures.
Material on potted plant on the left?
Maybe wood material on cabinet on far left is too dark?