Can i drink soda while pregnant ?

So im not a soda drinker at all... my parents raised me not to drink it at all.. but now that im pregnant sometimes i crave a coca cola to eat with my dinner or lunch. I do not drink alot of it just half the cup... but my mom said that the baby can become autistic and special needs if i drink it alot? Is that true???? Will my baby be ok if i drink alittle bit of it? Like i said i dont drink black soda everyday just like once a month.