Good bike shorts will make any ride more comfortable. That being said, I find that for rides up to about 15-20 miles, depending on which underwear I'm using, my bike shorts are unecessary...so I don't wear them for most of my commuting, just when I feel like it.

As far as clipless; they won't make you faster. They will however give you greater endurance and proper form. So I guess from that standpoint clipless will give you greater sustained speed over time, but not greater instantaneous speed.

There really is no "proper" time for either of these. Bike shorts are simply a comfort luxury that is dependent upon your comfort level with strolling about in spandex. Clipless are a neat technical innovation that a lot of people are hooked on, but not everybody. But it's never "too early" or even "too late" to try either.

Keep on riding. Even without a "training" regimen, if you just ride your normal ride, over time you'll see your speed has increased, and you don't even know when it happened. Nothing wrong with 14mph, as long as you're enjoying yourself.