The main thing you need to look out for in an instructor is him being keen to teach. You don't need the best flier in the club you want the one who is best able to communicate what he knows.

The question you forgot to ask is what your attitude should be. Art covered it fairly well. Listen to your instructor and give him a chance to teach you something. The fact that you have run R/C cars means that you have some useful information but please try to avoid telling your instructor that you already know it all. You'll soon find that even taxying a plane is harder/different to running a car and when it gets off the ground it's even more different.

As for how long it takes, the shortest I've seen personally is solo in 4 flights. Very unusual. The longest is about 5 years. You'll be somewhere in between. Most people seem to manage it in a season (say 1 to 8 months) but rushing to give up your instructor before you're really ready will cause you some serious expense down the road. It's a major cause of crashes .

Have fun

Steve