My abdomen is getting fat, my mom says its a roll. what do you think? i need a lot of answers please!?

i dunno if it is a roll or if its muscles, but its squishy (lol). i dont think i could be pregnant. my boyfriend did finger me though after i gave him a hand job & he d but i REALLY dont think he had sperm on his hand. but i haven't had my period for three months but im still irregular cuz i only started in september of 2008 & i haven't had any other symptoms of being pregnant. so what do you think? would it be squishy if i was pregnant? would it even be showing if i was 3 months pregnant? does being pregnant even start showing at the abdomen? is it normal to have a roll at the age of fifteen? someone please give me some answers!