Maybe it would say:
"Stop waiting."
"Take the risk."
"Trust yourself."
"Put the phone down."
"Start before you feel ready."
"Spend more time with the people you love."
Or perhaps the hardest truth of all...
"Become the person I had to become sooner."
Your future isn't created by tomorrow.
It's created by the choices you make today.
What do you think your future self would tell you right now?