for a tip on riding, take it one step at a time and a motorcycle riding course is always good. depends on how big you are. i wouldnt go over 600cc's such as a zzr600 or an R6, ninja 600, lt6...u get the idea.
There are only two sportbikes that are recomended by the manufacturers for beginners. The 250cc Kawasaki Ninja and the Honda CBR250r. Many young people die trying to learn on 600cc sportbikes. Statistically they are more dangerous than the liter class. Mainly because newbees think they are good for beginners. Both the 250 Ninja and the CBR250R will go over 100mph. If that is not good enough for a beginner then your train of thought is right in line with all the new riders that meet their fate on a 600cc sportbike. Every one of those new riders said to themselves because I am smarter, mature for my age, tall for my age, more careful than most, a quick learner, etc... I will not become a statistic. Look at the two bikes mentioned. They are great bikes and good for a beginner. Before you get any bike find out how much you would pay in insurance at Progressive.com.