Oh my goodness sweetheart.....no bueno with the Mountain Dew. There is also the development of diabetes as a big concern on top of the dehydration factor.
I was a big soda drinker up until I was 24 years old. It impacted my stomach the most, once I switch to water instead of soda I noticed I barely ever had a stomachache any more.
You are a determined young woman. Before you know it you will look at soda like, "meh...I'm really not a fan."