I'm gonna throw this at you just because I have been where you are right now...
Being as this is your first boat and you are unfamiliar with boating as a whole, a jet boat MAY be the way to go....
Why MAY?
Pros; cheap to buy, cheap to maintain, fairly straight forward for the average weekend mechanic to work on, pretty tough to break, no prop to worry about with the little guy.
Cons; loud, use lots of fuel, takes a bit of horsepower to get them to have some speed, tricky to drive if you have never driven a boat before (no motor, no steering), can't haul a lot of weight/crap/people.
You may consider looking into an I/O for some pretty simple reasons; like driving your dads station wagon s far as handling, a small block Chevy in a 20'er is almost a guaranteed 60mph as long as you don't buy an ocean scow, you can put 6 people, two ice chests, a dog, spare tools and ski equipment in it and only lose 3 or 4mph, run all day on a tank of gas, there quiet, so no worries about where to run it at (most lakes require mufflers and wet exhaust), and parts are easy to come by as long as you don't buy something obsolete.
Cons (to be fair); always worrying about the prop, can't really run the shallows (no offense but rookies have no business being in shallow rivers), a little more work as far as getting the boat in and out of the water (trimming up the out drive), and about twice the maintenance.
Our family has all flavors of boats, we have two I/O's, three jet boats, two sail boats, two inboard ski boats and an aluminum fishing boat with a whacker. I would be lying if I didn't say the jets were not the most fun...
Keep asking questions and write out a pros and cons list for yourself and be honest with yourself about it.
Your going to have to decide how much you will be using it too. Neither one is a good choice for two or three times a year. Which is why we (my family) have all been using the same boat for outings, only one boat to maintain because we are all too busy to use our junk more than twice a year each.

GT