Actually, it takes a little time to let google index you. To make it faster you can paste it on Submit url web tool, or try to use paid indexer which working fine too (especially if you are having a lot of links)
Yeah, it definitely seems like it may be time more than anything else. There are certainly no problems I can see with them on a technical level (guests can view them and they're not set to noindex/blocked in robots.txt), and the content seems like it should be decent enough for Google to index as well.
That said, have you tried promoting them a bit more too? Because from what I recall, Google tends to index content more quickly if it's being linked to from other websites, and your articles don't seem to be getting many links overall.