Because that's not something I am always thinking about, I can't give you an answer right away.
Because that's not something that I always have in mind, I can't answer you right this minute.
ご質問ありがとうございます。
① "Because that's not something I am always thinking about"＝「それは私がいつも考えていることではないので」
"I can't give you an answer right now."＝「今すぐ答えを言えません。」
② "Because that's not something that I always have in mind"＝「それは常に念頭にあることではないので、今すぐ答えられません。」
ご参考に。
アメリカ合衆国 
