I've asked a similar question to more experienced folks at the Classic Jet Aircraft Association (they fly jet warbirds such as the L-39 Albatros). To get an L-39 type rating (it's technically a LOA, not a type rating), you need 1000 hours. When I had 60 hours, I asked them what experience they recommended I get before flying a Jet warbird. I took notes on their advice, and I'll share it here. Of course, get your PPL first, in a normal plane such as a Cessna 172 or Piper Arrow. Here was their advice:
* Get an instrument (IFR) rating first. Get used to flying "in the system." This covers a lot of ground.
* Get complex time (complex = retractable gear, flaps, and constant-speed prop). Get time in bigger and faster aircraft.
* Get 500 hours of retract time before moving to the L-39 (putting the gear down should be second nature). If possible, get a multiengine rating.
* Get aerobatic lessons to get comfortable - start with a Citabria or something slower, then move to something like an Extra. (this step won't apply to business jets such as the Citation, although some upset training is probably a good idea).
I'm currently on this path. I just passed 400 hours, got my instrument rating last year. I'm flying a fairly fast single engine piston (a Columbia 400). This plane is "slippery", which means it's actually hard to slow down while you're descending from cruising altitude to your destination. Sometimes I have to start descending over 35 miles away from the destination airport. You have to plan your descents in advance. In fact, you have to plan everything in advance, because things move fast. In a jet, everything moves even faster. If I could afford it, I'd move up to a single engine turboprop. But I'll probably have to stick with the Columbia, which means I won't get the 500 hours of retract time they recommended. I'll have to get some retract time in something else, maybe a 182RG or who knows what.
So I guess you could something like:
1. Cessna 172 - get your PPL, and your IFR ticket in this. Rent.
2. Buy a Columbia or a Cirrus, or something comparable. Range: $300k (used) - $900k (new)
3. Get a single engine turboprop (Meridian, Pilatus PC-12, TBM-850, Denali, depending on how much you want to spend). Range: I'm not speaking from experience, but probably $1M - $5M, depending on year & options. Do you need a toilet? That costs more. Check out
http://philip.greenspun.com/flying/ - he has some good, straightforward reviews of several of these planes (and others).
4. Get a jet.
You may be able to skip step 2, but it will require more training on the next step if you want to be safe.
Have fun along the way. Maybe get some mountain training, or gliders, or tailwheel.