Hey that is exactly what I have done. Started at noon yesterday- or shall I say restarted at noon yesterday. So I am not 25 hours in. I had to do it this way because my eating was out of control and I just needed to stop it right away.
Thinking that I am going to start tomorrow just makes me eat more today...I try to have "one last" EVERYTHING. Do that a few days in a row and trying to start a fast just ends up making me bloated and confused.
Good luck. A few hours into a fast is a great place to start.