Download Krita on your PC first. It's actually free and can be used in most computers. >w < Tell ya what, it has a lotta brushes you could use for different stuff (sometimes, you don't even need skill for them)
Doesn't really matter XD I used to draw without a tablet when I was 12. All I used was the laptop touchpad (which 90% people have unless they use a mouse and computer) In Krita, there are brushes to make star effects and you could just move the cursor and mess around to make a galaxy art....lol some sort of 'milky way' they call it (?)