I still find it hard to believe you'd need anything bigger than a 15 inch bike. If you feel a bit cramped in the cockpit, then I'd consider lengthening the stem before going up a bike size. It's also important that you correctly set not just seat height, but the saddle's fore/aft position before concluding that a bike is too small.
Live with intention. Walk to the edge. Listen hard. Practice wellness. Play with abandon. Laugh. Choose with no regret. Continue to learn. Appreciate your friends. Do what you love. Live as if this is all there is.
--Mary Anne Radmacher