What Causes Swelling In The Lymph Node At The Crease Of My Inner Thigh?

hey guys.. im 12 and im a girl. i recently found a swollen lymph node near my underwear line in my leg crease next to my leg.. me and my mom are 100 percent sure its a lymph node.. and we dont think it meens anything serious because my mom said if it was serious we would prob know. because of other side effects id be having.. i think it origionated when i got a bladder infection a couple of days ago. is that possible? i would feel really good if i knew i was going to be alright. my mom said that we would watch it and see how it goes.. but is it possible to be from a bladder infection? its really small. and its rubery and i can move it.. please help me.. please