Should I be worried

So I have been reading this book and I'm worried because it's telling me that 95% of woman who had diets that were  good/excellent there babies came out very very healthy and 65 % of them who had diets that's were mostly junk there baby's were pre mature and stillborn. I don't eat to terrible but I wouldn't say I eat that great I eat veggies and drink a lot of milk and water I just wonder how healthy I have to eat i don't want to harm my baby i only have 3 months left and if I change my eating now to excellent will that help my baby a lot?