I cant moan during sex, is that normal?

I usually hold my breath and whenever i feel him real deep inside i gasp, but i dont think ive ever had a full orgasm? 
​He says he wants me to moan because it tell him he is doing a good job. I love our sex, but i just feel mostly embarrassed of moaning, mainly because i am forcing/faking it. 
​And we usually have sex quietly because we are at his house and his mom is right next to his room.