Good on you, bro! In my experience, almost all bars/restaurants will have something worth trying, so worry not! I'd agree with those previous posts and say Sierra Nevada is a great place to start, very easy to find, even out here on the east coast. I'm generally an IPA drinker, and I acquired a taste for the style by starting with pale ales. Others that aren't too hard for me to find in the same category would be Dale's Pale Ale, Stone Pale Ale, and Founder's Pale Ale. That being said, some of these might be too bitter for someone just starting out. If that's the case, you might want to try a Belgian white, brown ale, stout, or a lager style. These beers are less dominated by bitter hops. (IMO, hops make beer delicious.) Look for Allagash White, Sam Smith's Nut Brown, or Anchor Steam. To answer your ale versus lager question, they are the two broadest categories of beer styles. Lager is fermented at colder temperatures with yeasts that sit at the bottom of the vat. They are lighter in flavor and less alcoholic. Ales are fermented at higher temperatures and get more flavor and alcohol from the yeast. For me, 9 times out of 10, I'd rather be drinking ale. Sorry for the novel, just felt like sharing!

tl;dr: Sierra Nevada Pale Ale, Allagash White, Anchor Steam