yeah go let the pro's do it...
it is possible to diy, but honestly its not worth the hassle...
if its anything like mine u'll;
cut it too small,
cut wrong way round,
the wind will catch it & crease it (this happened to me, even tho there wasnt even a breeze, just went to put it on window & wind blew from nowhere, folded up & creased)
then theres the problem of getting it scratched if u use a hard squeegy..
air bubbles creeping in just as ur about to finish
curving the film around the back window
cutting around the window latch...
most places wont put the tint on for u if u have the roll, so u may just try and find some1 to do it on the side, or pay to have it done at by pro's - that way u'll know its 100% and u'll have a gurantee