It just means that you realize in that moment that's it's ti

that's是写错了,应该是that,因为 it's time to let go and move on是realize的宾语从句.
译文参考：这只是意味着：那时你意识到了是放手继续前进的时候了.
不明白的再问哟,请及时采纳,多谢!