Help!! Advice Please.

Alright so I know a lot of guys like to go down on girls and some girls have told me they like it when guys go down on them but I'm afraid. Everytime a guy ask me I say I think it's pretty gross but I'm just afraid. How do I know if it tastes good or bad for that matter? Can someone help me with this problem. Were you guys scared and afraid of this happening too on your first try? How did you get over it?