Flat belly help please?

Okay, i have been really obsessing about my body for the past few months.At start i did alot of biking every day and was forced to stop when it started to continously rain. I did cut the junk food then but when rain started i hit the couch and even stopped doing my pilates exercises. Now i do 10 leg ups a day,10 sit ups and 10 pilates ball kind of sit ups. I will raise for 10 every weak cause i don't want pain. I am cutting on all the junk food (chocolate,chips.ice cream etc.) but the breakfast,lunch and dinner, i really can't be the one that decides what to eat for that cause my mom keeps telling me i am not fat. I have 50 or 48 kg and i am 163-165 cm tall. I am not really fat but when i sit i hate the damn rolls. And my lower AND above tummy need to get tightened up. Trust me i tried walking; too boring. I tried running; i almost died and over-sweated after 5 minutes. I am not allowed to do much sports except for swimming and biking and roller blading because i have spine skoliosis. I'm 14,is there any chance i have still baby fat left? My friend tells me i do,she's 15 (almost 16) and she tells me i am still growing up. I know but,is it possible that this fat will go into boobs? lol. Silly questions but i really don't want to end up fat. I just want to tighten up a little bit. And please don't reccomend me any special things you have to buy,i am from europe and stuff is way expensive and does NOT work. Help? (: