Help! I want to ask this guy to the dance but...?

so at my school our valentines day dance is going to be turned into one of those girls ask guys to go with them, so no guys asking girls (a Sadie Hawkins)... i really like this guy and i want to be able to ask him to go with me but i am like scared to death with nervousness to ask him, does anyone have any good tips? i so really want to ask him and i really like him, so how can i ask him with out being nervous/less nervous! I also had the idea of asking him in a note if i couldnt manage to work up the courage before then, but do you htink a note would be good? or no? I would perfer to do it face to face but in a way i think i note might be ok?