The 23" inch bike might be a bit on the small size.
Based on your current knowledge of sizing, it would be advisable to check out some bike shops. They will at least give you an indication of proper sizing. Some of them may give you a quick bike fit.
Personally, I think I'd skip buying a bike on the Internet unless I was very sure of what I wanted. That, and the fact that in the long run, the bike shop will probably be a bit cheaper and provide you with a much more useful product that fits you.