Go to medical school and become a specialist of sorts and make quarter to half a million a year then buy a plane

Military is great IF you can get in. If not then get a technical degree that you can use as your backup plan if flying doesn't work out then just knock out your ratings and build hours. You'll never go straight to Fed Ex or UPS without having to do something first (regional, 135, military, etc), so find a couple routes that have worked for others and replicate that, or take the road less traveled. Either way my guess is even if you started now that you might not make it to where you want to go until you're 30 or so.... So, ya know, live your life and have some fun, learn some things, but work towards that goal every day and don't ever give up.