A Town Car, or either of it's panther platform siblings (Crown Vic, Grand Marquis (and 03-04 Marauder)) are a great choice for a first car. Reliable, affordable, attractive (IMO) and safe. Their body on frame construction, though antiquated to many, provides a solid platform which is praised for it's durability and smooth ride.
91-95 are prone to valve stem seal seepage (resulting in oil burning and as it becomes worse, puffs of smoke from the exhaust)
The 91-95 manifold is also prone to clogging the EGR passages. Luckily, that's fairly simple to clean out - an EGR flow insufficient code with higher mileage is a red flag for this problem.
96-01 are all potentially effected by the intake manifold front coolant crossover rupture issue. It's NBD to change, but if it has the composite crossover look into replacement before it leaves you stranded some time.
The brake lines on -97 models are suspectable to rusting out in harsh winter climates where lots of road salt is used. So inspect them right away. The 98+ models use rubber coated lines which helped a lot with this issue.
97+ have a revised steering gear which greatly improved on-center feel. The front of the chassis was redesigned and given rack and pinion for 03+, but they do ride stiffer than ever.
The 03 models had a few minor issues following the upgrades, most commonly LCM failure.
95 brought the 4r70w, but the 95 unit is weak. 96 a few enhancements (deep sump pan, new VB and case) to it, 97 even more (new accumulators for one) and more yet in '98. The '98+ units are pretty stout, even more so the 06+ 4r75E units, which have upgraded internals from the 4R75W.
That all said, I'm partial to the 98-02 models. If you like the keypad feature, get a 99- as 98s did not have it. Only thing I did not like was the revision to the speedometer face in 00, the 98-99 speedo was more attractive IMO.