Am I cantonese?

I have no doubt for my standard cantonese, but I begin having suspicion about that since I moved to Zhongshang, I can't understand their local cantonese, their mandarine are bad too, when I asked how much the vegetable is in cantonese whenI went to the market, they always answered me in mandarine, They thought that I was an exotic from another province, in my working place, I couldn't understand what my co-workers said when they were saying gossip about someone in their local cantonese, and I was lean over to hear what they said, but I couldn't understand, and I didn't mind it, It was non of my business. So I prefer speaking mandarine to my co-workers, altough they understand my meaning but I can't understand them.