Dear future self, 
I hope you've got your life figured out and I hope you're doing something cool in the STEM field. I hope you're programming and making robots. If you have kids please get rid of them unless they can walk then keep them for a couple years. Remind mom and dad that you love and appreciate them as well as all of your siblings. If you happen to have kids, who do they belong to? Have you traveled anywhere else outside the US yet? I hope you've found that someone who makes you happy in every way. 
Sincerely, your 2017 self