Stewart is spot on, most others are talking utter rubbish - the Porsche is a great car, very reliable, handles well, quick enough, parts are dirt cheap, and the car would be ideal for anyone - it's even got a hatchback & big boot!
As for insurance, it will be possible to insure a 924 as a classic - this is usually much, much cheaper than any modern car. Google 'classic car insurance' & ring around for some quotes.
Go ahead & buy it - and watch the faces of all the other teens as your 20 year old Porsche is quicker, more reliable & cheaper to run than their Fiestas & Corsas.
Good source for parts;
http://www.gsfcarparts.com
(Brake discs £24 a pair, pads £16.25, exhaust £50, water pump £24)
There are many forums on the web too that'll advise you what to check when buying. Good luck.