i cant make that big of poixel art im not that good so can i use something like 16 x 16 or 32 x 32

Do you mean for the whole screen, or for the sprites?

sprite but what do you mean by screen

The screen (the playing area) should be 160x144 pixels only. If you haven't already, you should read the FAQ and rules to avoid disqualification. I've updated the page with more pictures to help illustrate.