Nervous/Shy

my boyfriend has had about 2/3 sex partners before me he never let them go down on him and vice versa I was his first he went down on and he's my first in everything. he was wants me to give him head and I do too, he hasn't forced me or pressured me into anything. we've been together for almost 2 years now he's always gone down on ME & does all the work but never complained about me not doing the same. I really want to give him a bj but I'm scared that I'll be doing it wrong and hurting him especially with braces & tongue piecing but he told me that he doesn't Care if I hurted him, he also told me he'll guide me and teach me but I'm shy🙄.. (don't know if its really important but he's uncircumcised & pretty big too)

any tips?