It is still a great camera. My oldest grandson has the same camera and has been using it heavily for the last 4 years without a single problem.
The suggestions for researching the database here is a great one. It is also a good idea to stay with Pentax in the beginning.
I would make two additional suggestions. Try to buy and use lenses that use a 49mm filter thread. This way you can buy just one set of filters that will work with all your lenses. Next, buy a hood. If you stay with the first suggestion you can buy a 49mm screw in hood that will work fine with most of your lenses.
Over the years I have accumulated a small set of lenses for my Pentax K1000 SE that work beautifully. These are certainly not the only ones that will work but they make a great, light, easy to use set that covers most of the bases.
* Pentax M 35/2
* Pentax M 50/1.7
* Pentax M 85/2
* Pentax M 135/3.5
Then, go buy an inexpensive set of extension tubes and everyone of these can be used as a macro.
Once you feel comfortable with those lenses then you can look at wider lenses, the Pentax M 24 is a nice one, and you can go longer. There are lots of choices from 200mm on but the filters are usually larger and you will need to have a better feeling how you want to use it. If you will use it indoors a lot than it should have a faster aperture. The 200/4 may not work as well indoors but outdoors it is almost perfect.
Just my 2 cents.