The answer to your question is really very simple.

Stay away from the Extra until you feal confident you could fly any airplane. One poster aluded to the increased difficulty in landing. These low-wing acrobatic planes land at a higher speed than your trainer -- you will have to be very capable of keeping control of the plane right down to the ground. A trainer that is lined up onto the center of the runway can be let loose to float into a landing. If you treat the low-wing acrobatic like that you may stall it on landing and end up with a repair job.

I'm surprised that with all the posts on this subject no one really has a strong recommendation for a stick as a second plane. A stick (Super Stick, Ultra Stick, Ugly Stick, Big Stick, etc) still retain the capability for float to the ground landings and gives you the acrobatic capability not available with the trainer. Soon after the stick go to a funfly airplane -- it will definetly teach you how to throw an airplane around the sky and still allow you to float to a landing.

Another way to increase your confidense in landings is to try short final landings, i.e., make your downwind to base to final turn just in front of the beginning of the runway. This forces you to stay in control of the airplane right down to touch down -- once you master this it really seams to be an easier way to land than long floating final approaches, especially if you have obstacles to clear just prior to landing.

My 3 cents.