Wow, you really are brave. Good on you for keeping it,I don't know many girls that would act like you have.Having a disabled baby isn't all bad-my mum has worked with down's kids for years,and she loves them-she says they are unusually sweet and afectionate and can sometimes be really talented in certain areas.
Also,my cousin had her daughterChloe when she was 16.Chloe has a serious illness,I can't remember the name,but basically she's blind,can't walk,takes fits and has very limited speech.She's 9 now.My cousin has 3 other children now,the youngst was born a week ago.She's a truly amazing mother.You'll do just fine =]