Jimmy,
A couple things to keep in mind if you've never had any sour beer. Think of sour beer being totally unlike any regular beer, with the closest kinship being maybe a really dry saison with a moderately soured berliner. But generally, the world of sour beer is pretty broad and often drastically different than regular beer. I wouldnt start with a lambic. Lambic is kind of the kimchi of beers, quite funky and flat. My suggestion would be to start with a berliner, and maybe a brett saison, then jump to whatever. Also, give them a good chance. Dont think beer when you take that first sip. Many of them are more like a dry funky champagne than a beer. Plus many of the flavors that brett contributes are unlike anything else found in the food/beverage world. Hence the odd descriptors thrown around like barnyard and horsey. To me, a good brett is more like fermented pineapple with fresh leather. But its its own thing, so dont expect it to be exactly like anything.
Try the three sip rule. Let the 1st sip surprise you. Shake it off, you'll live. On the second sip start trying to figure out what that is. By the 3rd sip you'll be hooked. Should be...
Some common off flavors to look for are acetic acid (vinegar), buteric acid (vomity), and isovaleric acid (stinky feet). If you find a beer with those, its not good. Sour beer shouldnt be like that. Dont think that is what it should be like, and call us all crazy for drinking that.
Have fun!