Shrink my waistline!!!

Hi!

I am a very active female. I am 20 years old, 5"7 and about 130 lbs. I go to the gym usually about 5-6 times a week. My question is, what else can I do to shrink my waistline? Right now I am at about 27.5" but I feel like it just isn't getting any smaller!

I do resistance training every other day and 20 minutes of cardio in between those days. I'm also a vegetarian so I eat vegetables and seafood is my source of protein as well as supplements in shakes and protein bars. Is the cardio the problem? Meaning, I'm not doing enough? Any advice would be much appreciated! THANKS!