It’s a long time ago now.

[touchstone]

[FONT=&#23435] You must all be too young to remember man[/FONT]’[FONT=&#23435]s first visit to the moon. It[/FONT]’[FONT=&#23435]s a long time ago now. It was July 1969, and I was still a student.[/FONT][FONT=&#23435][/FONT]
[FONT=&#23435]([/FONT][FONT=&#23435]Target 3[/FONT][FONT=&#23435], Longman)[/FONT][FONT=&#23435][/FONT][FONT=&#23435]
I think [/FONT]‘[FONT=&#23435]It[/FONT]’[FONT=&#23435]s a long time ago[/FONT]’[FONT=&#23435] means [/FONT]‘[FONT=&#23435]It is a long time ago from now[/FONT]’[FONT=&#23435]. In another words, it means [/FONT]‘[FONT=&#23435]It happened a long time ago[/FONT]’[FONT=&#23435]. What do you say?[/FONT][FONT=&#23435][/FONT]
[FONT=&#23435]Thanks. [/FONT][FONT=&#23435][/FONT]

 

[BobGerr]

"It's a long time ago now."

The author is speaking in a conversational tone, and has perhaps for poetic reasons decided to use more words than necessary.

The simplest version of this sentence would be, "It was a long time ago."

There is really no need to use, "It's" or, "now" in the structure of this sentence but it allows for the word as spoken to represent the character of the speaker. The use of, "now" simply roots the sentence in the present for effect.