Struggles to initiate sex with bf

My boyfriend has told me that he wants me to feel free to initiate sex with him when I want it but I have such a hard time doing it. Asking for sex or just outright touching him sexually makes me feel weird and embarrassed. We’re both 23 years old, he has sexual experience whereas he’s really the first guy I’ve been intimate with. How can I overcome my aversion to asking for what I want?