ADVICE ME PLEASE

So ive been dealing with a girl. Shes my first. And shes went down on me multiple times. She says she gets pleasure out of pleasing me am that she’s content. I dont think its fair that shes given me head and I haven’t pleased her but I literally just cant get the nerve to do it (i think im gunna have to get drunk to relax or something) i have no problem with doing it i just get super nervous. Bc what if i dont like it. Bc i really like her and she definitely turns me on. But i dont how to start or what to do 🙄