這句的意思為何 now is it.

No, it is just a simple sentence like

This is it.

However, in your question, "this" is replaced with "now".

2012-05-05 13:10:28 補充：
我決定，如果有一個時刻是自僱 (自營)的好時機,現在正是時候

2012-05-05 14:11:19 補充：
I feel "I decided" translates as "我決定", sounds weird to myself. Therefore, I think, it might be more Chinese to translate as "我判斷"

2012-05-06 11:43:06 補充：
To shorten the sentence, or not to use "decide", you could write:

It is now (time) to start being self-emplyed !

2012-05-06 11:44:06 補充：
This way, the meaning of "decide" is embedded in the sentence.

now is it = 現在就是

(I think) NOW is the best time to start my own business.


is simpler English.

I, thus concluded, if there's ever a good time to be self-employed, now is it.

is better English.

2012-05-06 11:08:24 補充：
Mr. Big Paul is good English and I shall submit myself under his authority.

now is it => 就是現在!

now 也是一個名詞，許多字意本身就是名詞‧
Give me five. 拍一下手
Give me a high five. 高跳一拍