Not in the mood

Hi guys. So I'm only 23 and I'm never in the mood!! My SO is 26 and he is always in the mood. I was always in the mood around age 19 buts it's slowly died off and I feel like I'm WAYYYY to young to feel like this! Whenever we do have sex, I always enjoy myself and it feels great and I usually do have an orgasm but it's just getting into the mood that I just don't feel like. Is something wrong with Me or is this normal??