Running for my second ear

This will be my second marathon. My first one was 4 hrs and 48 mins. Do you reckon I can do it in 4 hours and 20 mins? That's knocking a whole 28 mins off my last run. I'd like to give it my best shot and would love you to sponsor me to support me. This run will require hours and hours of training, eating right, sleeping plenty, plus continuing to work as a nurse, all the while being a mum and wife. if worse came to worse and I get injured I still endeavor to walk it or run the half if i have to ;-)