I have added stripes to my vehicles before, not that hard to do. I screwed up some areas when i applied the stripes because i rushed some areas so take your time.
If you do have someone install them before you, just make sure its a good shop. Some shops will refuse to apply or overcharge to install aftermarket vinyl because you wont be using their material
I had never applied any decals except to model airplanes as a youngster, and I managed to stripe my own car. Watch a bunch of youtube videos, think things through, and take your time.