The first one is correct, but I'd say "지금은(=이제) 점심먹을 시간"^^
1) now - 지금(은)
2) it's time for - ~ ㄹ 시간
3) lunch - 점심
It could be "벌써 점심시간이네" in a more casual way.^^
Here are some examples regarding "it's time for something/to do something"
1) it's time for us to have a break
휴식 시간입니다.
2) it's time for moving
출발할 시간입니다.
3) it's time for breakfast
아침밥 먹을 시간입니다.
4) it's time for you to get up
일어날 시간입니다.
^________^