How do I get it up for guys? Help> 10 pts?

I am 21 and think i miiiight be gay. i haven't liked a guy, but i do think some are good looking. i try to get hard thinking about guys and doing stuff with them but i hardly even get up, i mean probably like 1/4...but even then thats generous. when i think of chicks i get up though. maybe i am just not sexually attracted to them? cause I honestly can't tell you the last time i got a full ere ction thinking of a dude, but a chick, well it was this morning when thinking of one. help?