Let's go back to my Question, is any mistakes or grammatical errors therein??
Well, I wouldn't say that using an indefinite article with dinner not being preceded by an adjective, is a mistake, but, as I wrote in my previous post, dinner, like other meals, prefers the so-called zero article to be used with it.
Originally Posted by english001
and one more thing, does it mean that if we want to be more specific we just have to put an ADJECTIVE as in, "I had a lovely dinner with my family" does it makes sense??
Yes, you use an adjective to be more specific about meals; though you can use the + (adjective) + meal, if you want to talk about a particular meal that you have had:
I had (a formal) dinner with Charles Dickenson, my ex-manager. The (formal) dinner was really unconventional.