As an anecdotal tack on (yeah, anecdotes aren't data, but still), I regularly run 12-15 miles with no additional beverages having drank only coffee before heading out. There's nothing magic about coffee that makes it somehow not usable fluid for hydration. Yes, staying hydrated is good, but you'll know if you need water - you'll feel thirsty!
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That's awesome, congrats on the progress! Those initial steps are by far the hardest, I think you're going to be really happy with your results over time. Post often!