Why is it so hard to get a g/f?

So, i've never had a real girlfiend, and im 17 which is kinda embarring. i don't think im hot but ive been told i am cute by some girls. im average height, athletic, and a bit skinny and live in aus. so yeah why cant i get a decent girlfriend. everyones saying girls like nice guys but all the girls go for are the idiots, and most of them are really ratty. like, no matter how hard i try i can't get a g/f. im nice, polite, trustworthy, etc but they just ignore it. How can i get a girlfiend coz im sick of being single and want someone to care for and to hang out with and stuff..? plzzz give me sum opinions oranything, thnx :)