Is Cantonese an old language

Yes. Some dialects of Cantonese have written language dated pre-2000BC. The spoken Cantonese dialect of Chinese beginnings are unknown with certainty but history dictates that most languages are verbal thousands of years before an alphabet was created for them, usually rudimentary symbols, the only surviving ones carved in stone. But conjecture is that symbols were drawn with charcoal also. But none survive today.

這是中國廣東..or

Zhè shì zhōngguó guǎngdōng

is "This is Cantonese Chinese"