Yeah, I am completely aware that these are things you already know. But if you're like me, interesting mental images won't hurt to remind you that ... well, hah, that you don't have any excuses. Acknowledge, slam, walk on. If you avoid being a "fat little baby" in your spiritual walk and regularly GROW UP, you will "bear fruit" from spiritual birth and on into old age.
Expect changes, make mistakes, learn. Wash, rinse, repeat. When we have committed ourselves to Jesus the natural result is that our behavioural choices will look like His too. If this is true of you, whether you are physically old or not, those who remain IN THE NOW AND THE NOT YET are truly going to live ... forever.