Cars don't like not being used, they get damp , road use dries them off , rubber perishes, joints dry up
I'd argue a car that's being used regularly at temperature needs less servicing than one that's sat around
I've never understood the insistence on low mileage , a London car with 25k over 5 years will have turned thousands of corners, hit thousands of speed bumps and been run from cold 2-3 times a day , or worse left for weeks unused all of which is bad for a car
One that's done 100k in the same period will have spent most of its life at temperature and run in a straight line on the motorway.
For the love of me I don't see how the OP is going to be able to drive this car for 8-10 years and that's if he keeps a blemish free driving history, a crash or some points and the insurance won't want to know.
I can think of a lot better things to spend the money on at 17 than a car I can't drive.