Perplexity just before the purchase

Good morning dear car friends , I am about to buy a Mazda MX 5 which I have already looked at personally and with which it should go eigtl today to the TÜV South used car check. It is about this car : http://suchen.mobile.de/…/details.html?… Within the family it became loud , that after all the value loss the cars is still worth 20 percent of the new price and I will not get a cent for the car in 4-5 years. That was already quite a shock for me, I am now 25 years old would like to buy my first car now, but also not to lose too much money. Of the Mx 5 one reads quite a lot positive and at present it fits to my driving profile, I drive mostly only to 2. in the car could take the car for transports if necessary from my mother, annual driving performance should be so about the 8000 kilometers. Have visited the car he stood very well there, after the Tüv Check should eigtl the contract be signed But now I’m afraid that I won’t be able to sell the car in 4 years and so I’m putting too much money in the sand. My original hope was that the car could be sold in 4-5 years already for 3500 … Vllt the whole thing can be evaluated by an expert here in the forum, I don’t really know about cars, had so far no car love greetings, Defensive driver