How can i imrove my Performance?

I 23M have been in my very first relationship with my current girlfriend 25F for about five years, before me, she’s been with both men and women, so she has way more experience than me.
Small but probably important detail: I am extremely introverted and shy, and I don’t feel like a very sexual and sensual Person.
Recently she’s been hinting that I am not doing a good Job in the bedroom, I always make her come first and can last up to an hour by now.
From time to time I try new positions or movements, but I still feel like a newbie and my girlfriend hinting that I’m not outgoing enough is making things really hard for me.
What can I try or do that will fulfill her more and how can I initiate sexy time (being verbal about it is turning her off)