sewing question

[gennyvieve.livejournal.com]

hey y'all!

i recently started sewing, and i am really enjoying it, but i have a question i'm hoping you can answer for me.....

i'm making a dress, and i changed the neckline, so now the pieces that would go on the inside don't fit, and my question is, can i just make a 3/4" hem along the neckline and be done with it? i guess since i have no real sewing knowledge, i just learned from watching mom, i don't understand WHY that piece has to be there.....i did ask mom and she said stability, but then couldn't really elaborate. i'm not trying to be difficult, i just like to understand why i have to do it.....

any imput would be great, and hopefully i will post photos when i'm done because this dress is totally rad. (and yes, the pattern on the material forces me to bring back "rad")